scholarly journals The Effect of Partial Pressures of Inert Gases on the Behaviour and Survival of the Heterotrich Ciliate Spirostomum Ambiguum

1976 ◽  
Vol 64 (3) ◽  
pp. 615-627
Author(s):  
S. MACDONALD ◽  
J. A. KITCHING
Keyword(s):  
Hydrostatic Pressure ◽  
Swimming Speed ◽  
Cell Damage ◽  
Inert Gases ◽  
Partial Pressures ◽  
Spirostomum Ambiguum ◽  
High Hydrostatic Pressures

A study has been made of the effects of helium, nitrogen and argon at partial pressures of 10–120 atm on the swimming speed, behaviour and survival of the heterotrich ciliate Spirostomum ambiguum. Experiments have also been carried out with hydrostatic pressure alone. Hydrostatic, helium and nitrogen pressures reduced the swimming speed approximately equally but pressure of argon reduced it to an even greater extent. Hydrostatic, helium, nitrogen and argon pressures caused a reduction in the number of reversals in a given time but the number of reversals/distance travelled did not change significantly. All the treatments increased the durations of individual forward movements. Pressures of helium, nitrogen and argon also increased the durations of reversals but at high hydrostatic pressures the durations of reversals were reduced. Argon caused cytolysis at 30–40 atm and nitrogen at 80 atm; helium did not cause any visible cell damage over periods of 1 h at 120 atm. Addition of substantial partial pressures of helium protected Spirostomum against partial pressures of argon which would otherwise have caused cytolysis. The increase of hydrostatic pressure may have been responsible.

Effects of helium and other inert gases on Echinosphaerium nucleofilium (protozoa, heliozoa)

1975 ◽  
Vol 63 (2) ◽  
pp. 467-481
Author(s):  
J. B. Miller ◽  
J. S. Aidley ◽  
J. A. Kitching
Keyword(s):  
Hydrostatic Pressure ◽  
Total Pressure ◽  
Cell Damage ◽  
Inert Gases ◽  
Gas Solubility ◽  
Reversal Effect ◽  
Pressure Reversal ◽  
Partial Pressures ◽  
Solubility Coefficients ◽  
Sites Of Action

The effects of helium, nitrogen, argon and krypton on Echinosphaerium nucleofilum (Heliozoa) have been studied at partial pressures of 10–130 atm. Additional experiments have been carried out with hydrostatic pressure alone. Helium causes shortening of the axopods over the whole range of pressures, and damage to the cell body at pressures of 60–90 atm, both with a maximum at 80 atm. These effects cannot be explained in terms of hydrostatic pressure alone; a ‘pressure reversal’ effect may be operating, causing the peak at 80 atm. Nitrogen also causes both cell damage and axopod shortening, the severity increasing with increasing pressure. Argon and krypton cause cell damage but no shortening. The order of potency for cell damage is krypton greater than argon greater than nitrogen greater than helium. It is suggested that there may be tuo sites of action, possibly the microtubules (for axopod shortening) and the cell membrane (for cell damage). In appropriate mixtures of helium and argon, both the cell damage usually caused by argon, and the axopod shortening usually caused by helium, are prevented. Possible mechanisms include the effects of hydrostatic pressure on gas solubility coefficients, reversal of the effects of the gases by the increase in total pressure, and competition for sites of action.

Effects of hydrostatic pressure and inert gases on platelet aggregation in vitro

1990 ◽  
Vol 69 (6) ◽  
pp. 2239-2247 ◽  
Author(s):  
D. M. Pickles ◽  
D. Ogston ◽  
A. G. Macdonald
Keyword(s):  
Platelet Aggregation ◽  
Hydrostatic Pressure ◽  
Maximum Degree ◽  
Platelet Rich Plasma ◽  
Control Level ◽  
Inert Gases ◽  
Partial Pressures ◽  
Compression Cycle ◽  
Anesthetic Potency

A novel cuvette was used to subject citrated platelet-rich plasma (PRP) to high hydrostatic pressure with negligible contamination by He (used for compression of the apparatus). Aggregation was induced at pressure by ADP and quantified turbidimetrically. The maximum degree of aggregation (MDA) was reduced from a control level of 82.2 to 53.6% by exposure to 101 ATA. Because decompression bubbles did not form, aggregation was also measured immediately after a compression cycle. After exposure to 101 ATA hydrostatic pressure, platelets responded normally to ADP at 1 ATA. In a matching apparatus, PRP was equilibrated with high partial pressures of inert gases. Normal physiological plasma Po2 and pH were maintained during equilibration. N2O (5 ATA) reduced the MDA from 86.5 (control) to 58.1%. N2 (51 ATA) reduced the MDA from 74.7 (control) to 51.6%, and 101 ATA Pn2 reduced the MDA from 78.0 (control) to 32.3%. He (100 ATA) reduced the MDA from 83.6 to 38.6%. It was concluded that platelet aggregation was relatively sensitive to hydrostatic pressure and less sensitive to inert gases than predicted from their anesthetic potency ratios.

scholarly journals Growth of Streptococcus faecalis under High Hydrostatic Pressure and High Partial Pressures of Inert Gases

1968 ◽  
Vol 52 (5) ◽  
pp. 810-824 ◽  
Author(s):  
Wallace O. Fenn ◽  
Robert E. Marquis
Keyword(s):  
Growth Rate ◽  
Nitrous Oxide ◽  
Lactic Acid ◽  
Hydrostatic Pressure ◽  
Inert Gases ◽  
Inhibitory Potency ◽  
Streptococcus Faecalis ◽  
Volume Increase ◽  
Partial Pressures ◽  
Gas Pressures

Growth of Streptococcus faecalis in a complex medium was inhibited by xenon, nitrous oxide, argon, and nitrogen at gas pressures of 41 atm or less. The order of inhibitory potency was: xenon and nitrous oxide > argon > nitrogen. Helium appeared to be impotent. Oxygen also inhibited streptococcal growth and it acted synergistically with narcotic gases. Growth was slowed somewhat by 41 atm hydrostatic pressure in the absence of narcotic gases, but the gas effects were greater than those due to pressure. In relation to the sensitivity of this bacterium to pressure, we found that the volume of cultures increased during growth in a volumeter or dilatometer, and that this dilatation was due mainly to glycolysis. A volume increase of 20.3 ± 3.6 ml/mole of lactic acid produced was measured, and this value was close to one of 24 ml/mole lactic acid given for muscle glycolysis, and interestingly, close to the theoretic volume increase of activation calculated from the depression of growth rate by pressure.

Sequential V˙a/Q˙ distributions in the normal rabbit by micropore membrane inlet mass spectrometry

2000 ◽  
Vol 89 (5) ◽  
pp. 1699-1708 ◽  
Author(s):  
James E. Baumgardner ◽  
In-Cheol Choi ◽  
Anton Vonk-Noordegraaf ◽  
H. Frederick Frasch ◽  
Gordon R. Neufeld ◽  
...  
Keyword(s):  
Blood Sample ◽  
Mass Spectrometer ◽  
Sample Volume ◽  
Inert Gases ◽  
Inert Gas ◽  
Total Blood ◽  
Membrane Inlet Mass Spectrometry ◽  
Arterial Blood ◽  
Partial Pressures ◽  
Regression Techniques

We developed micropore membrane inlet mass spectrometer (MMIMS) probes to rapidly measure inert-gas partial pressures in small blood samples. The mass spectrometer output was linearly related to inert-gas partial pressure ( r 2 of 0.996–1.000) and was nearly independent of large variations in inert-gas solubility in liquid samples. We infused six inert gases into five pentobarbital-anesthetized New Zealand rabbits and used the MMIMS system to measure inert-gas partial pressures in systemic and pulmonary arterial blood and in mixed expired gas samples. The retention and excretion data were transformed into distributions of ventilation-to-perfusion ratios (V˙a/Q˙) with the use of linear regression techniques. Distributions ofV˙a/Q˙ were unimodal and broad, consistent with prior reports in the normal rabbit. Total blood sample volume for eachV˙a/Q˙ distribution was 4 ml, and analysis time was 8 min. MMIMS provides a convenient method to perform the multiple inert-gas elimination technique rapidly and with small blood sample volumes.

Molecular Hydrogen Attenuates High Hydrostatic Pressure-Induced Neuronal Cell Damage by Reversing Dysfunction of Mitochondrial Electron Transfer Chain

2021 ◽  
Author(s):  
Zhuoyang Lu ◽  
Tiantian Zhang ◽  
Yachong Hu ◽  
Hui Liu ◽  
Li Cui ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Hydrostatic Pressure ◽  
High Hydrostatic Pressure ◽  
Cell Damage ◽  
Protective Agent ◽  
Protective Effects ◽  
Human Neuroblastoma ◽  
Electron Transfer Chain ◽  
Pathological Conditions ◽  
Transfer Chain

Abstract Cellular hydrostatic pressure beyond its normal range can induce the accumulation of reactive oxidative species (ROS) generated by mitochondria and lead to pathological conditions such as glaucomatous optic neuropathy. However, little is known about how the mitochondrial electron transfer chain (ETC) is affected by elevated pressure. Moreover, the protective effects of hydrogen on various pathological conditions have been observed by reductions in ROS, yet the role of hydrogen in high hydrostatic pressure (HHP)-induced cell damage remains obscure. The goal of this study was to investigate the effect of HHP on ETC activity and whether hydrogen exerts protective effects against HHP-induced damage in cultured neuronal cells. Cultured SH-SY5Y human neuroblastoma cells were exposed to an elevated ambient hydrostatic pressure of 50 mmHg for a period of 2 to 6 h. HHP impaired the activities of ETC complexes, and these effects were reversed by hydrogen. Significant increases in apoptotic rates and intracellular ROS levels were observed in HHP-treated SH-SY5Y cells. Hydrogen significantly inhibited the apoptotic rates and reduced the levels of ROS. These findings suggest that HHP induces cell damage by causing ETC dysfunction to increase oxidative stress and that hydrogen may act as a protective agent to alleviate HHP-induced neuronal injury.

Effects of Quenching Environment on the Structure of Melt- Spun Nd2Fe14B

1999 ◽  
Vol 577 ◽  
Author(s):  
M. J. Kramer ◽  
Yali Tang ◽  
K.W. Dennis ◽  
R. W. Mccallum
Keyword(s):  
Heat Transfer ◽  
Melt Spinning ◽  
Thermal Analyses ◽  
Inert Gases ◽  
Interfacial Heat Transfer Coefficient ◽  
Interfacial Heat Transfer ◽  
Melt Pool ◽  
Uniform Microstructure ◽  
Partial Pressures ◽  
Melt Spun

ABSTRACTMelt-spun Nd2Fe14B (2–14–1) ribbons were produced under active vacuum and different partial pressures of inert gases of Ar and He. Microstructure and thermal analyses were performed to understand the microstructural evolution and glass formability (GF) of the ribbons. He atmosphere enhances the quenchability of the ribbons over Ar and vacuum. Ribbons made under 250 Torr He have more uniform microstructure and smoother surfaces than those under 760 Torr He. The higher quenchability induced by He, which increases the interfacial heat transfer coefficient between the melt and rotating wheel during melt spinning, is due to its higher thermal conductivity compared to Ar. The lower pressure stabilizes the turbulence between the melt-pool and Cu wheel, enhancing the heat transfer resulting in a more uniform quench. As a result, a more uniform ribbon microstructure can be obtained at relatively low wheel speeds.

Diving medicine

2010 ◽  
pp. 1416-1422
Author(s):  
D.M. Denison ◽  
M.A. Glover
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Partial Pressure ◽  
Ambient Pressure ◽  
Inert Gases ◽  
Gas Mixture ◽  
Generalized Seizures ◽  
Partial Pressures ◽  
Diving Medicine ◽  
The Central Nervous System

Diving remains the principal means of exploring and exploiting shallower underwater zones. Immersion and rapid increase in pressure with depth cause most problems unique to diving. Gas density, partial pressures, and solubility vary proportionately with ambient pressure. At elevated partial pressure, nitrogen becomes narcotic, as can other inert gases, and contaminants barely detectable at the surface can become toxic as their partial pressures rise with depth. Hyperoxia irritates the lungs and the central nervous system, and sometimes causing generalized seizures. A safe gas mixture at depth can become hypoxic as the partial pressure of oxygen decreases during the return to surface....

The Partial Pressures of Vapors of Volatile Liquids in the Presence of Inert Gases

1931 ◽  
Vol 35 (4) ◽  
pp. 1068-1073 ◽  
Author(s):  
W. G. Beare ◽  
G. A. McVicar ◽  
J. B. Ferguson
Keyword(s):  
Inert Gases ◽  
Partial Pressures ◽  
Volatile Liquids

The Swimbladder of Deep-Sea Fish: The Swimbladder Wall is a Lipid-Rich Barrier to Oxygen Diffusion

1980 ◽  
Vol 60 (2) ◽  
pp. 263-276 ◽  
Author(s):  
J. B. Wittenberg ◽  
D. E. Copeland ◽  
F R. L. Haedrich ◽  
J. S. Child
Keyword(s):  
Hydrostatic Pressure ◽  
Partial Pressure ◽  
Sea Water ◽  
Teleost Fishes ◽  
Partial Pressures ◽  
The Difference ◽  
Neutrally Buoyant ◽  
Tissue Fluids ◽  
Considerable Depth ◽  
Sea Fish

The swimbladder of teleost fishes is a gas-filled sac which serves primarily to make the fish neutrally buoyant in sea water, but occasionally assumes other functions. The gas contained in the swimbladder is largely oxygen, at a pressure very close to the external hydrostatic pressure. The difference in gas partial pressure between the gaseous contents of the swimbladder and the blood and tissue fluids is large in fishes living at any considerable depth, for the hydrostatic pressure increases about 1 atm with each 10 m depth, while the partial pressures of gases in sea water and body fluids are relatively independent of depth and together give a pressure of only about 1 atm. The difference in partial pressure of oxygen alone across the wall of the swimbladder of a fish living at 3000 m depth is close to 300 atm.

Multiple inert gas elimination technique by micropore membrane inlet mass spectrometry—a comparison with reference gas chromatography

2013 ◽  
Vol 115 (8) ◽  
pp. 1107-1118 ◽  
Author(s):  
Moritz Kretzschmar ◽  
Thomas Schilling ◽  
Andreas Vogt ◽  
Hans Ulrich Rothen ◽  
João Batista Borges ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Lower Lobe ◽  
Inert Gases ◽  
Inert Gas ◽  
Membrane Inlet Mass Spectrometry ◽  
Real Time Analysis ◽  
Partial Pressures ◽  
A New Technique ◽  
Ventilation And Perfusion

The mismatching of alveolar ventilation and perfusion (VA/Q) is the major determinant of impaired gas exchange. The gold standard for measuring VA/Q distributions is based on measurements of the elimination and retention of infused inert gases. Conventional multiple inert gas elimination technique (MIGET) uses gas chromatography (GC) to measure the inert gas partial pressures, which requires tonometry of blood samples with a gas that can then be injected into the chromatograph. The method is laborious and requires meticulous care. A new technique based on micropore membrane inlet mass spectrometry (MMIMS) facilitates the handling of blood and gas samples and provides nearly real-time analysis. In this study we compared MIGET by GC and MMIMS in 10 piglets: 1) 3 with healthy lungs; 2) 4 with oleic acid injury; and 3) 3 with isolated left lower lobe ventilation. The different protocols ensured a large range of normal and abnormal VA/Q distributions. Eight inert gases (SF6, krypton, ethane, cyclopropane, desflurane, enflurane, diethyl ether, and acetone) were infused; six of these gases were measured with MMIMS, and six were measured with GC. We found close agreement of retention and excretion of the gases and the constructed VA/Q distributions between GC and MMIMS, and predicted PaO2 from both methods compared well with measured PaO2. VA/Q by GC produced more widely dispersed modes than MMIMS, explained in part by differences in the algorithms used to calculate VA/Q distributions. In conclusion, MMIMS enables faster measurement of VA/Q, is less demanding than GC, and produces comparable results.

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