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Arturo Tozzi, Minella R. Dynamics and metabolic effects of intestinal gases in healthy humans. Biochimie 2024; 221:81-90. [PMID: 38325747 DOI: 10.1016/j.biochi.2024.02.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2023] [Revised: 01/06/2024] [Accepted: 02/03/2024] [Indexed: 02/09/2024]
Abstract
Many living beings use exogenous and/or endogenous gases to attain evolutionary benefits. We make a comprehensive assessment of one of the major gaseous reservoirs in the human body, i.e., the bowel, providing extensive data that may serve as reference for future studies. We assess the intestinal gases in healthy humans, including their volume, composition, source and local distribution in proximal as well as distal gut. We analyse each one of the most abundant intestinal gases including nitrogen, oxygen, nitric oxide, carbon dioxide, methane, hydrogen, hydrogen sulfide, sulfur dioxide and cyanide. For every gas, we describe diffusive patterns, active trans-barrier transport dynamics, chemical properties, intra-/extra-intestinal metabolic effects mediated by intracellular, extracellular, paracrine and distant actions. Further, we highlight the local and systemic roles of gasotransmitters, i.e., signalling gaseous molecules that can freely diffuse through the intestinal cellular membranes. Yet, we provide testable hypotheses concerning the still unknown effects of some intestinal gases on the myenteric and submucosal neurons.
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Affiliation(s)
- Arturo Tozzi
- Center for Nonlinear Science, Department of Physics, University of North Texas, 1155 Union Circle, #311427, Denton, TX, 76203-5017, USA.
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2
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Moes MI, Elia A, Gennser M, Keramidas ME. Combined effects of mild hypothermia and nitrous-oxide-induced narcosis on manual and cognitive performance. Am J Physiol Regul Integr Comp Physiol 2024; 326:R197-R209. [PMID: 38189165 PMCID: PMC11283895 DOI: 10.1152/ajpregu.00246.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Revised: 12/18/2023] [Accepted: 01/02/2024] [Indexed: 01/09/2024]
Abstract
Divers are at enhanced risk of suffering from acute cognitive deterioration because of the low ambient temperatures and the narcotic action of inert gases inspired at high pressures. Yet, the behavioral effects of cold and inert gas narcosis have commonly been assessed in isolation and during short-term provocations. We therefore evaluated the interactive influence of mild hypothermia and narcosis engendered by a subanesthetic dose of nitrous oxide (N2O; a normobaric intervention analog of hyperbaric nitrogen) on cognitive function during prolonged iterative exposure. Fourteen men partook in two ∼12-h sessions (separated by ≥4 days), wherein they performed sequentially three 120-min cold (20°C) water immersions (CWIs), while inhaling, in a single-blinded manner, either normal air or a normoxic gas mixture containing 30% N2O. CWIs were separated by a 120-min rewarming in room-air breathing conditions. Before the first CWI and during each CWI, subjects performed a finger dexterity test, and the Spaceflight Cognitive Assessment Tool for Windows (WinSCAT) test assessing aspects of attention, memory, learning, and visuospatial ability. Rectal and skin temperatures were, on average, reduced by ∼1.2 °C and ∼8 °C, respectively (P < 0.001). Cooling per se impaired (P ≤ 0.01) only short-term memory (∼37%) and learning (∼18%); the impairments were limited to the first CWI. N2O also attenuated (P ≤ 0.02) short-term memory (∼37%) and learning (∼35%), but the reductions occurred in all CWIs. Furthermore, N2O invariably compromised finger dexterity, attention, concentration, working memory, and spatial processing (P < 0.05). The present results demonstrate that inert gas narcosis aggravates, in a persistent manner, basic and higher-order cognitive abilities during protracted cold exposure.
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Affiliation(s)
- Maaike I Moes
- Division of Environmental Physiology, Swedish Aerospace Physiology Center, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Antonis Elia
- Division of Environmental Physiology, Swedish Aerospace Physiology Center, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Mikael Gennser
- Division of Environmental Physiology, Swedish Aerospace Physiology Center, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Michail E Keramidas
- Division of Environmental Physiology, Swedish Aerospace Physiology Center, KTH Royal Institute of Technology, Stockholm, Sweden
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3
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Bosco G, Giacon TA, Paolocci N, Vezzoli A, Noce CD, Paganini M, Agrimi J, Garetto G, Cialoni D, D'Alessandro N, Camporesi EM, Mrakic-Sposta S. Dopamine/BDNF loss underscores narcosis cognitive impairment in divers: a proof of concept in a dry condition. Eur J Appl Physiol 2023; 123:143-158. [PMID: 36214902 DOI: 10.1007/s00421-022-05055-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Accepted: 09/18/2022] [Indexed: 01/20/2023]
Abstract
PURPOSE Divers can experience cognitive impairment due to inert gas narcosis (IGN) at depth. Brain-derived neurotrophic factor (BDNF) rules neuronal connectivity/metabolism to maintain cognitive function and protect tissues against oxidative stress (OxS). Dopamine and glutamate enhance BDNF bioavailability. Thus, we hypothesized that lower circulating BDNF levels (via lessened dopamine and/or glutamate release) underpin IGN in divers, while testing if BDNF loss is associated with increased OxS. METHODS To mimic IGN, we administered a deep narcosis test via a dry dive test (DDT) at 48 msw in a multiplace hyperbaric chamber to six well-trained divers. We collected: (1) saliva samples before DDT (T0), 25 msw (descending, T1), 48 msw (depth, T2), 25 msw (ascending, T3), 10 min after decompression (T4) to dopamine and/or reactive oxygen species (ROS) levels; (2) blood and urine samples at T0 and T4 for OxS too. We administered cognitive tests at T0, T2, and re-evaluated the divers at T4. RESULTS At 48 msw, all subjects experienced IGN, as revealed by the cognitive test failure. Dopamine and total antioxidant capacity (TAC) reached a nadir at T2 when ROS emission was maximal. At decompression (T4), a marked drop of BDNF/glutamate content was evidenced, coinciding with a persisting decline in dopamine and cognitive capacity. CONCLUSIONS Divers encounter IGN at - 48 msw, exhibiting a marked loss in circulating dopamine levels, likely accounting for BDNF-dependent impairment of mental capacity and heightened OxS. The decline in dopamine and BDNF appears to persist at decompression; thus, boosting dopamine/BDNF signaling via pharmacological or other intervention types might attenuate IGN in deep dives.
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Affiliation(s)
- Gerardo Bosco
- Department of Biomedical Sciences, University of Padova, 35131, Padova, Italy
- Division of Cardiology, Johns Hopkins Medical Institutions, Baltimore, MD, USA
- Institute of Clinical Physiology, National Research Council (CNR), 20162, Milano, Italy
- ATIP Center for Hyperbaric Medicine, Padova, Italy
| | | | - Nazareno Paolocci
- Department of Biomedical Sciences, University of Padova, 35131, Padova, Italy
- Division of Cardiology, Johns Hopkins Medical Institutions, Baltimore, MD, USA
| | - Alessandra Vezzoli
- Institute of Clinical Physiology, National Research Council (CNR), 20162, Milano, Italy
| | - Cinzia Della Noce
- Institute of Clinical Physiology, National Research Council (CNR), 20162, Milano, Italy
| | - Matteo Paganini
- Department of Biomedical Sciences, University of Padova, 35131, Padova, Italy
| | - Jacopo Agrimi
- Division of Cardiology, Johns Hopkins Medical Institutions, Baltimore, MD, USA
| | | | - Danilo Cialoni
- Department of Biomedical Sciences, University of Padova, 35131, Padova, Italy
- Division of Cardiology, Johns Hopkins Medical Institutions, Baltimore, MD, USA
- Institute of Clinical Physiology, National Research Council (CNR), 20162, Milano, Italy
- ATIP Center for Hyperbaric Medicine, Padova, Italy
- Dan Europe Foundation, Research Division, Roseto degli Abbruzzi, Teramo, Italy
| | | | | | - Simona Mrakic-Sposta
- Institute of Clinical Physiology, National Research Council (CNR), 20162, Milano, Italy.
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4
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Mankowska ND, Marcinkowska AB, Waskow M, Sharma RI, Kot J, Winklewski PJ. Reply to Vrijdag et al. Comment on “Mankowska et al. Critical Flicker Fusion Frequency: A Narrative Review. Medicina 2021, 57, 1096”. Medicina (B Aires) 2022; 58:medicina58060765. [PMID: 35744028 PMCID: PMC9228208 DOI: 10.3390/medicina58060765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 05/30/2022] [Accepted: 05/31/2022] [Indexed: 11/22/2022] Open
Affiliation(s)
- Natalia D. Mankowska
- Applied Cognitive Neuroscience Lab, Department of Human Physiology, Medical University of Gdansk, 80-210 Gdansk, Poland;
- Correspondence: ; Tel./Fax: +48-58-3491515
| | - Anna B. Marcinkowska
- Applied Cognitive Neuroscience Lab, Department of Human Physiology, Medical University of Gdansk, 80-210 Gdansk, Poland;
- 2nd Department of Radiology, Medical University of Gdansk, 80-210 Gdansk, Poland;
- Institute of Health Sciences, Pomeranian University in Slupsk, 76-200 Slupsk, Poland;
| | - Monika Waskow
- Institute of Health Sciences, Pomeranian University in Slupsk, 76-200 Slupsk, Poland;
| | - Rita I. Sharma
- Department of Human Physiology, Medical University of Gdansk, 80-210 Gdansk, Poland;
- Department of Anaesthesiology and Intensive Care, Medical University of Gdansk, 80-210 Gdansk, Poland
| | - Jacek Kot
- National Centre for Hyperbaric Medicine, Institute of Maritime and Tropical Medicine in Gdynia, Medical University of Gdansk, 80-210 Gdansk, Poland;
| | - Pawel J. Winklewski
- 2nd Department of Radiology, Medical University of Gdansk, 80-210 Gdansk, Poland;
- Institute of Health Sciences, Pomeranian University in Slupsk, 76-200 Slupsk, Poland;
- Department of Human Physiology, Medical University of Gdansk, 80-210 Gdansk, Poland;
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5
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Piispanen WW, Lundell RV, Tuominen LJ, Räisänen-Sokolowski AK. Assessment of Alertness and Cognitive Performance of Closed Circuit Rebreather Divers With the Critical Flicker Fusion Frequency Test in Arctic Diving Conditions. Front Physiol 2021; 12:722915. [PMID: 34447319 PMCID: PMC8384076 DOI: 10.3389/fphys.2021.722915] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Accepted: 07/12/2021] [Indexed: 12/29/2022] Open
Abstract
Introduction: Cold water imposes many risks to the diver. These risks include decompression illness, physical and cognitive impairment, and hypothermia. Cognitive impairment can be estimated using a critical flicker fusion frequency (CFFF) test, but this method has only been used in a few studies conducted in an open water environment. We studied the effect of the cold and a helium-containing mixed breathing gas on the cognition of closed circuit rebreather (CCR) divers. Materials and Methods: Twenty-three divers performed an identical dive with controlled trimix gas with a CCR device in an ice-covered quarry. They assessed their thermal comfort at four time points during the dive. In addition, their skin temperature was measured at 5-min intervals throughout the dive. The divers performed the CFFF test before the dive, at target depth, and after the dive. Results: A statistically significant increase of 111.7% in CFFF values was recorded during the dive compared to the pre-dive values (p < 0.0001). The values returned to the baseline after surfacing. There was a significant drop in the divers’ skin temperature of 0.48°C every 10 min during the dive (p < 0.001). The divers’ subjectively assessed thermal comfort also decreased during the dive (p = 0.01). Conclusion: Our findings showed that neither extreme cold water nor helium-containing mixed breathing gas had any influence on the general CFFF profile described in the previous studies from warmer water and where divers used other breathing gases. We hypothesize that cold-water diving and helium-containing breathing gases do not in these diving conditions cause clinically relevant cerebral impairment. Therefore, we conclude that CCR diving in these conditions is safe from the perspective of alertness and cognitive performance.
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Affiliation(s)
- Wilhelm W Piispanen
- Faculty of Medicine, University of Turku, Turku, Finland.,DAN Europe Research Division, Finnish Branch, Helsinki, Finland
| | - Richard V Lundell
- The Centre for Military Medicine, The Finnish Defense Forces, Helsinki, Finland.,Department of Pathology, Helsinki University, Helsinki, Finland
| | - Laura J Tuominen
- Department of Pathology, Helsinki University, Helsinki, Finland.,Anesthesia and Intensive Care Unit, Tampere University Hospital, Tampere, Finland
| | - Anne K Räisänen-Sokolowski
- DAN Europe Research Division, Finnish Branch, Helsinki, Finland.,The Centre for Military Medicine, The Finnish Defense Forces, Helsinki, Finland.,Department of Pathology, Helsinki University and Helsinki University Hospital, Helsinki, Finland
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6
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Tetzlaff K, Lemaitre F, Burgstahler C, Luetkens JA, Eichhorn L. Going to Extremes of Lung Physiology-Deep Breath-Hold Diving. Front Physiol 2021; 12:710429. [PMID: 34305657 PMCID: PMC8299524 DOI: 10.3389/fphys.2021.710429] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2021] [Accepted: 06/16/2021] [Indexed: 01/03/2023] Open
Abstract
Breath-hold diving involves environmental challenges, such as water immersion, hydrostatic pressure, and asphyxia, that put the respiratory system under stress. While training and inherent individual factors may increase tolerance to these challenges, the limits of human respiratory physiology will be reached quickly during deep breath-hold dives. Nonetheless, world records in deep breath-hold diving of more than 214 m of seawater have considerably exceeded predictions from human physiology. Investigations of elite breath-hold divers and their achievements revised our understanding of possible physiological adaptations in humans and revealed techniques such as glossopharyngeal breathing as being essential to achieve extremes in breath-hold diving performance. These techniques allow elite athletes to increase total lung capacity and minimize residual volume, thereby reducing thoracic squeeze. However, the inability of human lungs to collapse early during descent enables respiratory gas exchange to continue at greater depths, forcing nitrogen (N2) out of the alveolar space to dissolve in body tissues. This will increase risk of N2 narcosis and decompression stress. Clinical cases of stroke-like syndromes after single deep breath-hold dives point to possible mechanisms of decompression stress, caused by N2 entering the vasculature upon ascent from these deep dives. Mechanisms of neurological injury and inert gas narcosis during deep breath-hold dives are still incompletely understood. This review addresses possible hypotheses and elucidates factors that may contribute to pathophysiology of deep freediving accidents. Awareness of the unique challenges to pulmonary physiology at depth is paramount to assess medical risks of deep breath-hold diving.
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Affiliation(s)
- Kay Tetzlaff
- Department of Sports Medicine, University Hospital of Tübingen, Tübingen, Germany
| | - Frederic Lemaitre
- Faculte des Sciences du Sport et de l'Education Physique, Universite de Rouen, Rouen, France
| | - Christof Burgstahler
- Department of Sports Medicine, University Hospital of Tübingen, Tübingen, Germany
| | | | - Lars Eichhorn
- Department of Anesthesiology and Intensive Care Medicine, University Hospital Bonn, Bonn, Germany
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7
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Kirshenboim I, Aviner B, Itskovits E, Zaslaver A, Broday L. Dopamine-dependent biphasic behaviour under 'deep diving' conditions in Caenorhabditis elegans. Proc Biol Sci 2021; 288:20210128. [PMID: 33715430 PMCID: PMC7944115 DOI: 10.1098/rspb.2021.0128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Underwater divers are susceptible to neurological risks due to their exposure to increased pressure. Absorption of elevated partial pressure of inert gases such as helium and nitrogen may lead to nitrogen narcosis. Although the symptoms of nitrogen narcosis are known, the molecular mechanisms underlying these symptoms have not been elucidated. Here, we examined the behaviour of the soil nematode Caenorhabditis elegans under scuba diving conditions. We analysed wild-type animals and mutants in the dopamine pathway under hyperbaric conditions, using several gas compositions and under varying pressure levels. We found that the animals changed their speed on a flat bacterial surface in response to pressure in a biphasic mode that depended on dopamine. Dopamine-deficient cat-2 mutant animals did not exhibit a biphasic response in high pressure, while the extracellular accumulation of dopamine in dat-1 mutant animals mildly influenced this response. Our data demonstrate that in C. elegans, similarly to mammalian systems, dopamine signalling is involved in the response to high pressure. This study establishes C. elegans as a powerful system to elucidate the molecular mechanisms that underly nitrogen toxicity in response to high pressure.
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Affiliation(s)
- Inbar Kirshenboim
- Department of Cell and Developmental Biology, School of Medicine, Tel Aviv University, Tel Aviv, Israel.,Israel Naval Medical Institute, Israel Defense Forces Medical Corps, Haifa, Israel
| | - Ben Aviner
- Israel Naval Medical Institute, Israel Defense Forces Medical Corps, Haifa, Israel
| | - Eyal Itskovits
- Department of Genetics, Silberman Institute of Life Science, Edmond J. Safra Campus, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel
| | - Alon Zaslaver
- Department of Genetics, Silberman Institute of Life Science, Edmond J. Safra Campus, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel
| | - Limor Broday
- Department of Cell and Developmental Biology, School of Medicine, Tel Aviv University, Tel Aviv, Israel
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8
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Lafère P, Hemelryck W, Germonpré P, Matity L, Guerrero F, Balestra C. Early detection of diving-related cognitive impairment of different nitrogen-oxygen gas mixtures using critical flicker fusion frequency. Diving Hyperb Med 2019; 49:119-126. [PMID: 31177518 DOI: 10.28920/dhm49.2.119-126] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 03/08/2019] [Indexed: 01/03/2023]
Abstract
INTRODUCTION Cognitive impairment related to inert gas narcosis (IGN) is a threat to diving safety and operations at depth that might be reduced by using enriched air nitrox (EANx) mixtures. Using critical flicker fusion frequency (CFFF), a possible early detection of cognitive abilities/cerebral arousal impairment when breathing different oxygen (O2) fractions was investigated. METHODS Eight male volunteers performed, in random order, two dry chamber dives breathing either air or EANx40 (40% O₂-60% nitrogen) for 20 minutes (min) at 0.4 MPa. Cognition and arousal were assessed before the dive; upon arrival at 0.4 MPa; after 15 min exposure at 0.4 MPa; on surfacing and 30 min post-dive using behavioural computer-based testing psychology experiment building language (PEBL) and by CFFF while continuously recording brain oxygenation with near-infrared spectroscopy. RESULTS In both breathing conditions, CFFF and PEBL demonstrated a significant inverse correlation (Pearson r of -0.90, P < 0.0001), improved cognitive abilities/cerebral arousal occurred upon arrival at 0.4 MPa followed by a progressive deterioration. Initial brain activation was associated with a significant increase in oxyhaemoglobin (HbO2) and a simultaneous decrease of deoxyhaemoglobin (HHb). The magnitude of the changes was significantly greater under EANx (P = 0.038). CONCLUSIONS Since changes were not related to haemodynamic variables, HbO₂ and HHb values indicate a significant, O₂-dependent activation in the prefrontal cortex. Owing to the correlation with some tests from the PEBL, CFFF could be a convenient measure of cognitive performance/ability in extreme environments, likely under the direct influence of oxygen partial pressure, a potent modulator of IGN symptoms.
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Affiliation(s)
- Pierre Lafère
- DAN Europe Research Division, Roseto, Italy.,Laboratoire ORPHY, EA 4324, UFR sciences et techniques, Université de Bretagne Occidentale, Brest, France.,Environmental, Occupational, Ageing (Integrative) Physiology Laboratory, Haute Ecole Bruxelles-Brabant (HE2B), Brussels, Belgium.,Corresponding author: Pierre Lafère, Laboratoire ORPHY, EA 4324, UFR sciences et techniques, Université de Bretagne Occidentale, 6 Avenue Le Gorgeu - CS 93837, 29238 Brest Cedex 3, France,
| | - Walter Hemelryck
- DAN Europe Research Division, Roseto, Italy.,Environmental, Occupational, Ageing (Integrative) Physiology Laboratory, Haute Ecole Bruxelles-Brabant (HE2B), Brussels, Belgium
| | - Peter Germonpré
- DAN Europe Research Division, Roseto, Italy.,Centre for Hyperbaric Oxygen Therapy, Military Hospital 'Queen Astrid', Brussels
| | | | - François Guerrero
- DAN Europe Research Division, Roseto, Italy.,Laboratoire ORPHY, EA 4324, UFR sciences et techniques, Université de Bretagne Occidentale, Brest, France
| | - Costantino Balestra
- DAN Europe Research Division, Roseto, Italy.,Environmental, Occupational, Ageing (Integrative) Physiology Laboratory, Haute Ecole Bruxelles-Brabant (HE2B), Brussels, Belgium.,Anatomical Research and Clinical Studies (ARCS), Vrije Universiteit Brussel (V.U.B.), Brussels.,Anatomical Research Training and Education (ARTE), Vrije Universiteit Brussel (V.U.B.).,Motor Sciences, Université Libre De Bruxelles (U.L.B.), Brussels
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9
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Lozano R, Marín R, Santacruz MJ, Frutos AJ. Blood urea levels associated to antidepressant drug treatment: Role of nitrogen and nitric oxide. Indian J Psychiatry 2019; 61:314-315. [PMID: 31142913 PMCID: PMC6532462 DOI: 10.4103/psychiatry.indianjpsychiatry_141_10] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Roberto Lozano
- Department of Pharmacy, Hospital of Our Lady of Grace, Zaragoza, Spain. E-mail:
| | - Reyes Marín
- Department of Psychiatry, Hospital of Our Lady of Grace, Zaragoza, Spain
| | | | - Alberto-José Frutos
- Department of Pharmacy, Hospital Clinico Universitario "Lozano Blesa", Zaragoza, Spain
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10
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Rocco M, Pelaia P, Di Benedetto P, Conte G, Maggi L, Fiorelli S, Mercieri M, Balestra C, De Blasi RA. Inert gas narcosis in scuba diving, different gases different reactions. Eur J Appl Physiol 2018; 119:247-255. [PMID: 30350155 DOI: 10.1007/s00421-018-4020-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Accepted: 10/13/2018] [Indexed: 12/25/2022]
Abstract
PURPOSE Underwater divers face several potential neurological hazards when breathing compressed gas mixtures including nitrogen narcosis which can impact diver's safety. Various human studies have clearly demonstrated brain impairment due to nitrogen narcosis in divers at 4 ATA using critical flicker fusion frequency (CFFF) as a cortical performance indicator. However, recently some authors have proposed a probable adaptive phenomenon during repetitive exposure to high nitrogen pressure in rats, where they found a reversal effect on dopamine release. METHODS Sixty experienced divers breathing Air, Trimix or Heliox, were studied during an open water dive to a depth of 6 ATA with a square profile testing CFFF measurement before (T0), during the dive upon arriving at the bottom (6 ATA) (T1), 20 min of bottom time (T2), and at 5 m (1.5 ATA) (T3). RESULTS CFFF results showed a slight increase in alertness and arousal during the deep dive regardless of the gas mixture breathed. The percent change in CFFF values at T1 and T2 differed among the three groups being lower in the air group than in the other groups. All CFFF values returned to basal values 5 min before the final ascent at 5 m (T3), but the Trimix measurements were still slightly better than those at T0. CONCLUSIONS Our results highlight that nitrogen and oxygen alone and in combination can produce neuronal excitability or depression in a dose-related response.
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Affiliation(s)
- Monica Rocco
- Department of Surgical and Medical Science and Translational Medicine, Anesthesia and Intensive Care, Sapienza University, Rome, Italy.
| | - P Pelaia
- Department of Biomedical Sciences and Public Health, Anesthesia and Intensive Care, Università Politecnica delle Marche Torrette, Ancona, Italy
| | - P Di Benedetto
- Azienda Ospedaliero, Universitaria Sant'Andrea, Rome, Italy
| | - G Conte
- Department of Informatics Engineering, University Politecnica delle Marche, Ancona, Italy
| | - L Maggi
- Anesthesia and Intensive Care, Università Campus Biomedico, Rome, Italy
| | - S Fiorelli
- Department of Surgical and Medical Science and Translational Medicine, Anesthesia and Intensive Care, Sapienza University, Rome, Italy
| | - M Mercieri
- Department of Surgical and Medical Science and Translational Medicine, Anesthesia and Intensive Care, Sapienza University, Rome, Italy
| | - C Balestra
- Environmental, Occupational and Ageing (Integrative) Physiology Lab, Haute Ecole Bruxelles-Brabant (HE2B), Brussels, Belgium
| | - R A De Blasi
- Department of Surgical and Medical Science and Translational Medicine, Anesthesia and Intensive Care, Sapienza University, Rome, Italy
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11
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Nitrogen narcosis induced by repetitive hyperbaric nitrogen oxygen mixture exposure impairs long-term cognitive function in newborn mice. PLoS One 2018; 13:e0196611. [PMID: 29698458 PMCID: PMC5919656 DOI: 10.1371/journal.pone.0196611] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Accepted: 04/15/2018] [Indexed: 01/07/2023] Open
Abstract
Human beings are exposed to compressed air or a nitrogen-oxygen mixture, they will produce signs and symptoms of nitrogen narcosis such as amnesia or even loss of memory, which may be disappeared once back to the normobaric environment. This study was designed to investigate the effect of nitrogen narcosis induced by repetitive hyperbaric nitrogen-oxygen mixture exposure on long-term cognitive function in newborn mice and the underlying mechanisms. The electroencephalogram frequency was decreased while the amplitude was increased in a pressure-dependent manner during 0.6, 1.2, 1.8 MPa (million pascal) nitrogen-oxygen mixture exposures in adult mice. Nitrogen narcosis in postnatal days 7-9 mice but not in adult mice induced by repetitive hyperbaric exposure prolonged the latency to find the platform and decreased the number of platform-site crossovers during Morris water maze tests, and reduced the time in the center during the open field tests. An increase in the expression of cleaved caspase-3 in the hippocampus and cortex were observed immediately on the first day after hyperbaric exposure, and this lasted for seven days. Additionally, nitrogen narcosis induced loss of the dendritic spines but not of the neurons, which may mainly account for the cognitive dysfunction. Nitrogen narcosis induced long-term cognitive and emotional dysfunction in the postnatal mice but not in the adult mice, which may result from neuronal apoptosis and especially reduction of dendritic spines of neurons.
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12
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Freiberger JJ, Derrick BJ, Natoli MJ, Akushevich I, Schinazi EA, Parker C, Stolp BW, Bennett PB, Vann RD, Dunworth SAS, Moon RE. Assessment of the interaction of hyperbaric N2, CO2, and O2 on psychomotor performance in divers. J Appl Physiol (1985) 2016; 121:953-964. [PMID: 27633739 DOI: 10.1152/japplphysiol.00534.2016] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 09/02/2016] [Indexed: 11/22/2022] Open
Abstract
Diving narcosis results from the complex interaction of gases, activities, and environmental conditions. We hypothesized that these interactions could be separated into their component parts. Where previous studies have tested single cognitive tasks sequentially, we varied inspired partial pressures of CO2, N2, and O2 in immersed, exercising subjects while assessing multitasking performance with the Multi-Attribute Task Battery II (MATB-II) flight simulator. Cognitive performance was tested under 20 conditions of gas partial pressure and exercise in 42 male subjects meeting U.S. Navy age and fitness profiles. Inspired nitrogen (N2) and oxygen (O2) partial pressures were 0, 4.5, and 5.6 ATA and 0.21, 1.0, and 1.22 ATA, respectively, at rest and during 100-W immersed exercise with and without 0.075-ATA CO2 Linear regression modeled the association of gas partial pressure with task performance while controlling for exercise, hypercapnic ventilatory response, dive training, video game frequency, and age. Subjects served as their own controls. Impairment of memory, attention, and planning, but not motor tasks, was associated with N2 partial pressures >4.5 ATA. Sea level O2 at 0.925 ATA partially rescued motor and memory reaction time impaired by 0.075-ATA CO2; however, at hyperbaric pressures an unexpectedly strong interaction between CO2, N2, and exercise caused incapacitating narcosis with amnesia, which was augmented by O2 Perception of narcosis was not correlated with actual scores. The relative contributions of factors associated with diving narcosis will be useful to predict the effects of gas mixtures and exercise conditions on the cognitive performance of divers. The O2 effects are consistent with O2 narcosis or enhanced O2 toxicity.
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Affiliation(s)
- J J Freiberger
- Duke Center for Hyperbaric Medicine and Environmental Physiology and Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina
| | - B J Derrick
- Duke Center for Hyperbaric Medicine and Environmental Physiology and Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina
| | - M J Natoli
- Duke Center for Hyperbaric Medicine and Environmental Physiology and Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina
| | - I Akushevich
- Duke Center for Hyperbaric Medicine and Environmental Physiology and Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina
| | - E A Schinazi
- Duke Center for Hyperbaric Medicine and Environmental Physiology and Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina
| | - C Parker
- Duke Center for Hyperbaric Medicine and Environmental Physiology and Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina
| | - B W Stolp
- Duke Center for Hyperbaric Medicine and Environmental Physiology and Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina
| | - P B Bennett
- Duke Center for Hyperbaric Medicine and Environmental Physiology and Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina
| | - R D Vann
- Duke Center for Hyperbaric Medicine and Environmental Physiology and Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina
| | - S A S Dunworth
- Duke Center for Hyperbaric Medicine and Environmental Physiology and Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina
| | - R E Moon
- Duke Center for Hyperbaric Medicine and Environmental Physiology and Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina
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