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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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All sourcesNASA NTRSDOE OSTI
NASA NTRS1979

Project Explorer - Student experiments aboard the Space Shuttle

Project Explorer, a program of high school student experiments in space in a Space Shuttle self-contained payload unit (Getaway Special), sponsored by the Alabama Space and Rocket Center (ASRC) in cooperation with four Alabama universities is presented. Organizations aspects of the project, which is intended to promote public awareness of the space program and encourage space research, are considered, and the proposal selection procedure is outlined. The projects selected for inclusion in the self-contained payload canister purchased in 1977 and expected to be flown on an early shuttle mission include experiments on alloy solidification, electric plating, whisker growth, chick embryo development and human blood freezing, and an amateur radio experiment. Integration support activities planned and underway are summarized, and possible uses for a second payload canister purchased by ASRC are discussed.

Buckbee, E.↗
NASA NTRS1994

Weightlessness and the human skeleton: A new perspective

It is now clear after more than two decades of space exploration that one of the major short- and long-term effects of microgravity on the human body is the loss of bone. The purpose of this presentation will be to review the data regarding the impact of microgravity and bed rest on calcium and bone metabolism. The author takes the position in this Socratic debate that the effect of microgravity on bone metabolism can be either reversed or mitigated. As we begins to contemplate long-duration space flight and habitation of Space Station Freedom and the moon, one of the issues that needs to be addressed is whether humans need to maintain a skeleton that has been adapted for the one-g force on earth. Clearly, in the foreseeable future, a healthy and structurally sound skeleton will be required for astronauts to shuttle back and forth from earth to the moon, space station, and Mars. Based on most available data from bed-rest studies and the short- and long-duration microgravity experiences by astronauts and cosmonauts, bone loss is a fact of life in this environment. With the rapid advances in understanding of bone physiology it is now possible to contemplate measures that can prevent or mitigate microgravity-induced bone loss. Will the new therapeutic approaches for enhancing bone mineralization be useful for preventing significant bone loss during long-term space flight? Are there other approaches such as exercise and electrical stimulation that can be used to mitigate the impact of microgravity on the skeleton? A recent study that evaluated the effect of microgravity on bone modeling in developing chick embryos may perhaps provide a new perspective about the impact of microgravity on bone metabolism.

Holick, Michael F.↗
NASA NTRS1994

Neuritogenesis: A model for space radiation effects on the central nervous system

Pivotal to the astronauts' functional integrity and survival during long space flights are the strategies to deal with space radiations. The majority of the cellular studies in this area emphasize simple endpoints such as growth related events which, although useful to understand the nature of primary cell injury, have poor predictive value for extrapolation to more complex tissues such as the central nervous system (CNS). In order to assess the radiation damage on neural cell populations, we developed an in vitro model in which neuronal differentiation, neurite extension, and synaptogenesis occur under controlled conditions. The model exploits chick embryo neural explants to study the effects of radiations on neuritogenesis. In addition, neurobiological problems associated with long-term space flights are discussed.

Vazquez, M. E.↗
NASA NTRS1998

Effect of Microgravity on Afferent Innervation

Presentations and publications are: (1) an audiovisual summary web presentation on results from SLM-MIR avian experiments. A color presentation summarizing results from the SLM-MIR and STS-29 avian experiments; (2) color threshold and ratio of S 100B MAP5, NF68/200, GABA and GAD; (3) chicken (Gallus domesticus) inner ear afferents; (4) microgravity in the STS-29 Space Shuttle Discovery affected the vestibular system of chick embryos; (5) expression of S 100B in sensory and secretory cells of the vertebrate inner ear; (6) otoconia biogenesis, phylogeny, composition and functional attributes;(7) the glycan keratin sulfate in inner ear crystals; (8) elliptical-P cells in the avian perilymphatic interface of the tegmentum vasculosum; and (9) LAMP2c and S100B upregulation in brain stem after VIIIth nerve deafferentation.

Source record↗
NASA NTRS1997

Endothelial Cell Morphology and Migration are Altered by Changes in Gravitational Fields

Many of the physiological changes of the cardiovascular system during space flight may originate from the dysfunction of basic biological mechanisms caused by microgravity. The weightlessness affects the system when blood and other fluids move to the upper body causing the heart to enlarge to handle the increased blood flow to the upper extremities and decrease circulating volume. Increase arterial pressure triggers baroreceptors which signal the brain to adjust heart rate. Hemodynarnic studies indicate that the microgravity-induced headward fluid redistribution results in various cardiovascular changes such as; alteration of vascular permeability resulting in lipid accumulation in the lumen of the vasculature and degeneration of the the vascular wall, capillary alteration with extensive endothelial invagination. Achieving a true microgravity environment in ground based studies for prolonged periods is virtually impossible. The application of vector-averaged gravity to mammalian cells using horizontal clinostat produces alterations of cellular behavior similar to those observed in microgravity. Similarly, the low shear, horizontally rotating bioreactor (originally designed by NASA) also duplicates several properties of microgravity. Additionally, increasing gravity, i.e., hypcrgravity is easily achieved. Hypergravity has been found to increase the proliferation of several different cell lines (e.g., chick embryo fibroblasts) while decreasing cell motility and slowing liver regeneration following partial hepatectomy. The effect of altered gravity on cells maybe similar to those of other physical forces, i.e. shear stress. Previous studies examining laminar flow and shear stress on endothelial cells found that the cells elongate, orient with the direction of flow, and reorganize their F-actin structure, with concomitant increase in cell stiffness. These studies suggest that alterations in the gravity environment will change the behavior of most cells, including vascular cells. However, few studies have been directed at assessing the effect of altered gravitational field on vascular cell fiction and metabolism, Using image analysis we examined how bovine aortic endothelial cells altered their morphological characteristics and their response to a denudation injury when cells were subjected to simulated microgravity and hypergravity.

Melhado, Caroline↗
NASA NTRS1997

Calmodulin-Dependent Protein Kinase mediates Hypergravity-Induced Changes in F-Actin Expression by Endothelial Cells

A number of basic cellular functions, e.g., electrolyte concentration cell growth rate, glucose utilization, bone formation, response to growth stimulation and exocytosis are modified by microgravity or during spaceflight. Studies with intact animal during spaceflights have found lipid accumulations within the lumen of the vasculature and degeneration of the vascular wall. Capillary alterations with extensive endothelial invaginations were also seen. Hemodynamic studies have shown that there is a redistribution of blood from the lower extremities to the upper part of the body; this will alter vascular permeability, resulting in leakage into surrounding tissues. These studies indicate that changes in gravity will affect a number of physiological systems, including the vasculature. However, few studies have addressed the effect of microgravity on vascular cell function and metabolism. A major problem with ground based studies is that achieving a true microgravity hand, environment for prolonged period is not possible. On the other increasing gravity (i.e., hypergravity) is easily achieved. Several researchers have shown that hypergravity will increase the proliferation of several different cell limes (e.g., chick embryo fibroblasts) while decreasing cell motility and slowing liver regeneration following partial hepatectomy. These studies suggest that hypergravity will alter the behavior of most cells. Several investigators have shown that hypergravity affects the expression of the early response genes (c-fos and c-myc) and the activation of several protein kinases (PK's) in cells (10,11). In this study we investigated whether hypergravity alters the expression of f-actin by aortic endothelial cells, and the possible role of protein kinases (calmodulin(II)-dependent and PKA) as mediators of these effects.

Love, Felisha D.↗
NASA NTRS1997

Hypergravity Alters the Susceptibility of Cells to Anoxia-Reoxygenation Injury

Gravity is a physical force, much like shear stress or mechanical stretch, and should affect organ and cellular function. Researchers have shown that gravity plays a role in ventilation and blood flow distribution, gas exchange, alveolar size and mechanical stresses within the lung. Short exposure to microgravity produced marked alterations in lung blood flow and ventilation distribution while hypergravity exaggerated the regional differences in lung structure and function resulting in reduced ventilation at the base and no ventilation of the upper half of the lung. Microgravity also decreased metabolic activity in cardiac cells, WI-38 embryonic lung cells, and human lymphocytes. Rats, in the tail-suspended head-down tilt model, experienced transient loss of lung water, contrary to an expected increase due to pooling of blood in the pulmonary vasculature. Hypergravity has also been found to increase the proliferation of several different cell lines (e.g., chick embryo fibroblasts) while decreasing cell motility and slowing liver regeneration following partial hepatectomy. These studies show that changes in the gravity environment will affect several aspects of organ and cellular function and produce major change in blood flow and tissue/organ perfusion. However, these past studies have not addressed whether ischemia-reperfusion injury will be exacerbated or ameliorated by changes in the gravity environment, e.g., space flight. Currently, nothing is known about how gravity will affect the susceptibility of different lung and vascular cells to this type of injury. We conducted studies that addressed the following question: Does the susceptibility of lung fibroblasts, vascular smooth muscle, and endothelial cells to anoxia/reoxygenation injury change following exposure to hypergravity conditions?

McCloud, Henry↗
NASA NTRS2001

Effect of Serum from Chickens Treated with Clenbuterol on Myosin Accumulation, Beta-Adrenergic Receptor Population, and Cyclic AM Synthesis in Embryonic Chicken Skeletal Muscle Cell Cultures

Broiler chickens at 35 days of age were fed 1 ppm clenbuterol for 14 days. This level of dietary clenbuterol led to 5-7% increases in weights of leg and breast muscle tissue. At the end of the 14-day period, serum was prepared from both control and clenbuterol-treated chickens and was then employed as a component of cell culture media at a final concentration of 20% (v/v). Muscle cell cultures were prepared from both the leg and breast muscle groups of twelve-day chick embryos. Treatment groups included control chicken serum to which 10 nM, 50 nM, and 1 micron clenbuterol had been added, as well as cells grown in media containing 10% horse serum. Cultures were subjected to each treatment for 3 days beginning on the seventh day in culture. Neither the percent fusion nor the number of nuclei in myotubes were significantly affected by any of the treatments. The quantity of MHC was not increased by serum from clenbuterol-treated chickens in either breast and leg muscle cultures; however, MHC quantity was 50- 100% higher in cultures grown in control chicken serum to which 10 nM and 50 nM clenbuterol had also been added. The Beta-AR population was 4,000-7,000 Beta-AR per cell in cultures grown in chicken serum, with leg muscle cultures having approximately 25-30% more receptors than breast muscle cultures. Receptor population was not significantly affected by the presence of clenbuterol or by the presence of serum from clenbuterol-treated chickens. In contrast, the Beta-AR population in leg and breast muscle cultures grown in the presence of 10% horse serum was 18,000-20,000 Beta-AR per cell. Basal concentration of cAMP was not significantly affected by any of the treatments. When cultures grown in chicken serum were stimulated for 10 min with 1 micron isoproterenol, limited increases of 12-20% in cAMP concentration above basal levels were observed. However, when cultures grown in the presence of horse serum were stimulated with 1 micron isoproterenol, increases of 600-800 % in cAMP concentration above basal levels were observed. Thus, not only did cells grown in horse serum have a higher Beta-AR population, each receptor had a higher capacity for cAMP synthesis following isoproterenol stimulation. Finally, the hypothesis was tested that clenbuterol exerts its action on muscle protein content by changes in cAMP concentration. No correlation was apparent between basal cAMP concentration and MHC content.

Young, R. B.↗
NASA NTRS2002

Effect of Serum from Chickens Treated with Clenbuterol on Myosin Accumulation, Beta-Adrenergic Receptor Population, and Cyclic AMP Synthesis in Embryonic Chicken Skeletal Muscle Cell Cultures

Broiler chickens at 35 d of age were fed 1 ppm clenbuterol for 14 d. This level of dietary clenbuterol led to 5-7% increases in the weights of leg and breast muscle tissue. At the end of the 14-d period, serum was prepared from both control and clenbuterol-treated chickens, and was then employed as a component of cell culture media at a final concentration of 20% (v/v). Muscle cell cultures were prepared from both the leg and the breast muscle groups of 12-d chick embryos. Treatment groups included control chicken serum to which 10 nM, 50 nM, and 1 uM clenbuterol had been added, as well as cells grown in media containing 10% horse serum. Cultures were subjected to each treatment for 3 d, beginning on the seventh d in culture. Neither the percent fusion nor the number of nuclei in myotubes was significantly affected by any of the treatments. The quantity of myosin heavy chains (MHCs) was not increased by serum from clenbuterol-treated chickens in either breast or leg muscle cultures; however, the MHC quantity was 50-150% higher in cultures grown in control chicken serum to which 10 and 50 nM clenbuterol had also been added. The B-adrenergic receptor (betaAR) population was 4000-7000 betaARs per cell in cultures grown in chicken serum with leg muscle cultures having approximately 25-30% more receptors than breast muscle Culture. Receptor population was not significantly affected by the presence of clenbuterol or by the presence of serum from clenbuterol-treated chickens. In contrast, the betaAR Population in leg and breast muscle cultures grown in the presence of 10% horse serum was 16,000-18,000 betaARs per cell. Basal concentration of cyclic adenosine 3':5'monophosphate (cAMP) was not significantly affected by the treatments. When cultures grown in chicken serum were stimulated for 10 min with 1 uM isoproterenol, limited increases of 12-20% in cAMP Concentration above the. basal levels were observed. However, when cultures grown in the presence of horse serum were stimulated with 1 uM isoproterenol, cAMP concentration was stimulated 5- to 9-fold above the basal levels. Thus, not only did cells, grown in horse serum have a higher PAR population, but also each receptor had a higher capacity for cAMP synthesis following isoproterenol stimulation. Finally, the hypothesis that clenbuterol exerts its action on muscle protein content by changes in cAMP concentration was tested. No correlation was apparent between basal cAMP concentration and MHC content.

Young, Ronald B.↗
NASA NTRS1985

Morphogenesis and calcification of the statoconia in the chick (Gallus domesticus) embryo - Implications for future studies

The morphogenesis of the statoconia in the chick, Gallus domesticus, injected with a carbon anhydrase inhibitor is studied. The preparation of the embryo specimens for analysis is described. The early, middle, and late stages of embryonic development are examined. The data reveal that acetozolamide inhibits statoconia formation in the middle stage of development and the calcification process follows statoconia formation. The spatial relationship between the development of type 1 and type 2 hair cells and the appearance and maturation of the statoconia is investigated.

Fermin, C. D.↗
NASA NTRS1995

Neural tuning characteristics of auditory primary afferents in the chicken embryo

Primary afferent activity was recorded from the cochlear ganglion in chicken embryos (Gallus domesticus) at 19 days of incubation (E19). The ganglion was accessed via the recessus scala tympani and impaled with glass micropipettes. Frequency tuning curves were obtained using a computerized threshold tracking procedure. Tuning curves were evaluated to determine characteristics frequencies (CFs), CF thresholds, slopes of low and high frequency flanks, and tip sharpness (Q10dB). The majority of tuning curves exhibited the typical 'V' shape described for older birds and, on average, appeared relatively mature based on mean values for CF thresholds (59.6 +/- 20.3 dBSPL) and tip sharpness (Q10dB = 5.2 +/- 3). The mean slopes of low (61.9 +/- 37 dB/octave) and high (64.6 +/- 33 dB/octave) frequency flanks although comparable were somewhat less than those reported for 21-day-old chickens. Approximately 14% of the tuning curves displayed an unusual 'saw-tooth' pattern. CFs ranged from 188 to 1623 Hz. The highest CF was well below those reported for post-hatch birds. In addition, a broader range of Q10dB values (1.2 to 16.9) may related to a greater variability in embryonic tuning curves. Overall, these data suggest that an impressive functional maturity exists in the embryo at E19. The most significant sign of immaturity was the limited expression of high frequencies. It is argued that the limited high CF in part may be due to the developing middle ear transfer function and/or to a functionally immature cochlear base.

Non-NASA Center↗
NASA NTRS1993

Effects of microgravity on vestibular ontogeny: direct physiological and anatomical measurements following space flight (STS-29)

Does space flight change gravity receptor development? The present study measured vestibular form and function in birds flown as embryos for 5 days in earth orbit (STS-29). No major changes in vestibular gross morphology were found. Vestibular response mean amplitudes and latencies were unaffected by space flight. However, the results of measuring vestibular thresholds were mixed and abnormal responses in 3 of the 8 flight animals raise important questions.

NASA Discipline Neuroscience↗
NASA NTRS1992

Phosphorylation of the budgerigar fledgling disease virus major capsid protein VP1

The structural proteins of the budgerigar fledgling disease virus, the first known nonmammalian polyomavirus, were analyzed by isoelectric focusing and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The major capsid protein VP1 was found to be composed of at least five distinct species having isoelectric points ranging from pH 6.45 to 5.85. By analogy with the murine polyomavirus, these species apparently result from different modifications of an initial translation product. Primary chicken embryo cells were infected in the presence of 32Pi to determine whether the virus structural proteins were modified by phosphorylation. SDS-PAGE of the purified virus structural proteins demonstrated that VP1 (along with both minor capsid proteins) was phosphorylated. Two-dimensional analysis of the radiolabeled virus showed phosphorylation of only the two most acidic isoelectric species of VP1, indicating that this posttranslational modification contributes to VP1 species heterogeneity. Phosphoamino acid analysis of 32P-labeled VP1 revealed that phosphoserine is the only phosphoamino acid present in the VP1 protein.

Non-NASA Center↗
NASA NTRS2003

Expression of Prox1 defines regions of the avian otocyst that give rise to sensory or neural cells

The simple primordium of the inner ear (otocyst) differentiates into many cell types, including sensory neurons and hair cells. We examined expression of the divergent homeobox transcription factor, cProx1, during otocyst development in chickens. Nuclear cProx1 protein is not evident in the otic placode but emerges in the otic cup by stage 12. At stage 16, cProx1-positive nuclei are scattered continuously throughout the neuroepithelium, from anteroventral to posteromedial. These labeled cells are neural precursors; they express betaIII-tubulin and migrate to the cochleovestibular ganglion between stages 13 and 21. By stage 18, two areas develop a dense pattern of cProx1 expression in which every nucleus is labeled. These areas emerge at the anterior and posterior extremes of the band of scattered cProx1 expression and express the sensory markers cSerrate1 and Cath1 by stage 23. Four discrete patches of dense cProx1 expression appear by stage 23 that correspond to the future superior crista, lateral crista, saccular macula, and posterior crista, as confirmed by immunolabeling for hair cell antigen (HCA) by stage 29. The remaining sensory epithelia display a dense pattern of cProx1 expression and label for HCA by stage 29. In the basilar papilla, nuclear cProx1 expression is down-regulated in most hair cells by stage 37 and in many supporting cells by stage 40. Our findings show that regions of the otocyst that give rise to neurons or hair cells are distinguished by their relative density of cProx1-positive nuclei, and suggest a role for cProx1 in the genesis of these cell types.

NASA Discipline Developmental Biology↗
NASA NTRS2003

An algorithm for neurite outgrowth reconstruction

We present a numerical method which provides the ability to analyze digitized microscope images of retinal explants and quantify neurite outgrowth. Few parameters are required as input and limited user interaction is necessary to process an entire experiment of images. This eliminates fatigue related errors and user-related bias common to manual analysis. The method does not rely on stained images and handles images of variable quality. The algorithm is used to determine time and dose dependent, in vitro, neurotoxic effects of 1 GeV per nucleon iron particles in retinal explants. No neurotoxic effects are detected until 72 h after exposure; at 72 h, significant reductions of neurite outgrowth occurred at doses higher than 10 cGy.

NASA Program Biomedical Research and Countermeasur↗
NASA NTRS1999

An overview of vertebrate mineralization with emphasis on collagen-mineral interaction

The nucleation, growth, and development of mineral crystals through their interaction principally with collagen in normal bone and calcifying tendon have been elaborated by applying a number of different techniques for analysis of the inorganic and organic constituents of these tissues. The methods have included conventional and high voltage electron microscopy, electron diffraction, microscopic tomography and 3D image reconstruction, and atomic force microscopy. This summary presents results of these studies that have now characterized the size, shape, and aspects of the chemical nature of the crystals as well as their orientation, alignment, location, and distribution with respect to collagen. These data have provided the means for understanding more completely the formation and strength of the collagen-mineral composite present in most vertebrate calcifying tissues and, from that information, a basis for the adaptation of such tissues under mechanical constraints. In the context of the latter point, other data are given showing effects on collagen in bone cell cultures subjected to the unloading parameters of spaceflight. Implications of these results may be particularly relevant to explaining loss of bone by humans and other vertebrate animals during missions in space, during situations of extended fracture healing, long-term bedrest, physical immobilization, and related conditions. In a broader sense, the data speak to the response of bone and mineralized vertebrate tissues to changes in gravitational loading and applied mechanical forces in general.

Non-NASA Center↗
NASA NTRS2001

Vitamin C-sulfate inhibits mineralization in chondrocyte cultures: a caveat

Differentiating chick limb-bud mesenchymal cell micro-mass cultures routinely mineralize in the presence of 10% fetal calf serum, antibiotics, 4 mM inorganic phosphate (or 2.5 mM beta-glycerophosphate), 0.3 mg/ml glutamine and either 25 microg/ml vitamin C or 5-12 microg/ml vitamin C-sulfate. The failure of these cultures to produce a mineralized matrix (assessed by electron microscopy, 45Ca uptake and Fourier transform infrared microscopy) led to the evaluation of each of these additives. We report here that the "stable" vitamin C-sulfate (ascorbic acid-2-sulfate) causes increased sulfate incorporation into the cartilage matrix. Furthermore, the release of sulfate from the vitamin C derivative appears to be responsible for the inhibition of mineral deposition, as demonstrated in cultures with equimolar amounts of vitamin C and sodium sulfate.

NASA Discipline Musculoskeletal↗
NASA NTRS2000

Effect of electrical stimulation on beta-adrenergic receptor population and cyclic amp production in chicken and rat skeletal muscle cell cultures

Expression of the beta-adrenergic receptor (betaAR) and its coupling to cyclic AMP (cAMP) synthesis are important components of the signaling system that controls muscle atrophy and hypertrophy, and the goal of this study was to determine if electrical stimulation in a pattern simulating slow muscle contraction would alter the betaAR response in primary cultures of avian and mammalian skeletal muscle cells. Specifically, chicken skeletal muscle cells and rat skeletal muscle cells that had been grown for 7 d in culture were subjected to electrical stimulation for an additional 2 d at a pulse frequency of 0.5 pulses/sec and a pulse duration of 200 msec. In chicken skeletal muscle cells, the betaAR population was not significantly affected by electrical stimulation; however, the ability of these cells to synthesize cyclic AMP was reduced by approximately one-half. In contrast, the betaAR population in rat muscle cells was increased slightly but not significantly by electrical stimulation, and the ability of these cells to synthesize cyclic AMP was increased by almost twofold. The basal levels of intracellular cyclic AMP in neither rat muscle cells nor chicken muscle cells were affected by electrical stimulation.

Muscle, Skeletal/cytology↗