Biological evaluation of various spacecraft cabin atmospheres, I

Hamilton, Robert W.; Doebbler, G. F.; Schreiner, H. R.

doi:10.1007/bf00929292

Cited by 3 publications

(3 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…They concluded that long-term exposure to a Hx atmosphere had little to no biochemical or metabolic effects on mice, rats, adult rabbits or heterotherms [19][20][21] . The data reported in the present developmental study concur with the earlier research conducted by Hamilton et al [20] in their study of Hx exposure in rats and mice.…”

Section: Discussionmentioning

confidence: 99%

“…In research conducted for NASA, Hamilton et al [19][20][21] investigated the use of He and other non-N 2 inert gases for their potential as a carrier gas for O 2 during extended space flight. They concluded that long-term exposure to a Hx atmosphere had little to no biochemical or metabolic effects on mice, rats, adult rabbits or heterotherms [19][20][21] .…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Growth and Development in a Heliox Incubator Environment: A Long-Term Safety Study

Singhaus¹,

Utidjian²,

Akins

et al. 2006

Neonatology

View full text Add to dashboard Cite

Background: Neonates exposed to mechanical ventilation may develop bronchopulmonary dysplasia (BPD). BPD neonates exhibit a 25–30% increase in energy expenditure which may decrease the rate of growth and development. Heliox has been shown to improve pulmonary function and may decrease energy expenditure. We hypothesized that heliox would provide a safe environment for sustained growth and development. Objective: To assess the safety of the heliox environment we observed developmental milestones; recorded changes in weight, total length, limb length and head circumference; measured blood chemistries; compared primary organ and muscle weights, and analyzed muscle enzymatic activity. Design/Methods: Four-day-old rabbit pups (n = 27) were randomized into control (21% O₂; 79% N₂) or heliox (21% O₂; 79% He) groups, then raised for 14 days at 26.7°C and 50% relative humidity. Pups were euthanized on day 14, blood drawn and primary organs, diaphragm and gastrocnemius weighed and snap-frozen. Results: All pups thrived in both environments, achieving expected developmental milestones. There were no physiologically significant group differences in weight, growth factors, tissue weight, blood chemistry or muscle enzyme activity. Conclusions: No observed long-term differences in growth or development. Results demonstrated that long-term heliox exposure is safe in this rabbit model. These data suggest that heliox administration may provide time for pulmonary improvement in the BPD population, warranting appropriate clinical trials.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Growth and Development in a Heliox Incubator Environment: A Long-Term Safety Study

Singhaus¹,

Utidjian²,

Akins

et al. 2006

Neonatology

View full text Add to dashboard Cite

show abstract

“…Current interest in helium in the fields of underwater biology and aerospace has centred on this gas as a possible substitute for, or supplement to, nitrogen in the normal terrestrial atmosphere. In this respect, helium has been evaluated as a spacecraft cabin atmosphere (Hamilton et al, 1970) and it is the inert gas recommended by the U.S. Navy for treatment of decompression sickness or the 'bends' (U.S. Navy Diving Manual, 1972).…”

Section: Introductionmentioning

confidence: 99%

Hypobaric helium atmospheres for light and electron microscopy of mammalian cells

Lyon

Kraus

Parsons

1976

Journal of Microscopy

View full text Add to dashboard Cite

SUMMARY The development of electron microscope environmental/hydration chambers (EMC's) for the examination of living biological specimens has necessitated a search for a suitable gaseous environment that is compatible with both electron imaging and cell survival. Helium has a lower electron scattering cross section than air. The effects of hydrated helium and hydrated air atmospheres in an EMC at pressures 50–200 Torr were examined with a JEM 200 transmission electron microscope operated at 200 kV and 22°C. Results showed that whereas 200 Torr of air reduced beam transmission by more than 90% under these conditions, 200 Torr of moist helium only reduced beam transmission by 30%. The effects of sub‐atmospheric or hypobaric helium atmospheres on human white blood cells attached to glass coverslips were investigated by phase‐contrast light microscopy in a simulated EMC or light microscope environmental chamber (LMC) at 37°C. No gross morphological changes were observed in cells held at pressures of 300 Torr of moist helium for exposure times of 15 min. At pressures below 300 Torr, morphological changes occurred more rapidly as the pressure was reduced. At the lowest pressures tested (60 and 80 Torr) 50% of the cell populations died within 6–7 min. The development of morphological changes produced by hypobaric stress followed a characteristic pattern. The filopodia, or microvilli attaching the cells to the substrate, became withdrawn, with only occasional retraction fibres remaining. Blebs appeared around the cell surface and increased in size as hypobaric exposures progressed. Vacuoles, or clear spherical regions, appeared within the cytoplasm and the overall shape of the cells became circular. The cells became flatter during circularization, showing an apparent 2–2.5× increase in size as they respread on the substrate. Concurrently, the cytoplasm appeared oedematous and the cytoplasmic granules exhibited Brownian‐like motion. If hypobaric exposure was continued much beyond this latter stage, the cells were irrecoverable and the majority died after lysis of the cell membrane. It is apparent from this and other studies that mammalian cells begin to exhibit signs of stress when held at pressures below 300 Torr. This stress can lead to rapid killing of the cells by membrane lysis at lower pressure. A moist helium atmosphere of 300 Torr should permit at least 45% beam transmission in a conventional transmission electron microscope at 200 kV and should prove to be a major constituent of a supportive atmosphere suitable for maintaining cell viability and normal morphology during electron microscopy of living cells. The other major parameter (apart from radiation damage) for good quality electron imaging of living cells exhibiting various forms of motility and intracellular movement, is that of the depth of the surrounding aqueous medium. The possibility exists that media layers sufficiently deep to prevent immobility caused by surface tension effects, may prove to be a limiting factor for successful electron imaging.

show abstract

Embryogenesis in 100% O2 at reduced pressure

Weiss

Grimard

1971

Space Life Sciences

View full text Add to dashboard Cite

Biological evaluation of various spacecraft cabin atmospheres, I

Cited by 3 publications

References 27 publications

Growth and Development in a Heliox Incubator Environment: A Long-Term Safety Study

Growth and Development in a Heliox Incubator Environment: A Long-Term Safety Study

Hypobaric helium atmospheres for light and electron microscopy of mammalian cells

Embryogenesis in 100% O2 at reduced pressure

Contact Info

Product

Resources

About