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At least 1,531 records · Page 85
All sourcesNASA NTRSDOE OSTI
NASA NTRS1982

Body composition data from the rat subjects of Cosmos 1129 experiment K-316

The effects of 18.5 days of weightlessness on the body composition of young, growing, male laboratory rats were examined. Three groups of 5 rats each were examined. It is indicated that exposure of young, growing, male rats to 18.5 days of weightlessness produces: (1) no effect on the quantity of fat stored by the body; (2) a slight reduction in the quantity of fat free tissue laid down by the body; (3) a small reduction in the fraction of water contained by the fat free body mass; (4) a similar reduction in the fraction of water contained by the fat free skin and fat free carcass; (5) a shift in relative distribution of the total body water from skin to viscera; (6) a diminution in the fraction of extracellular water contained by the fat free body; (7) no effect on the fraction of total skeletal musculature contained by the fat free body, as indicated by body creatine content; (8) a sizeable reduction in the fraction of bone mineral contained by the fat free body, as calculated from body calcium content. The nature of the physiological changes induced by unloading from Earth gravity in the mammalian organism are illustrated.

Pace, N.↗
NASA NTRS1980

Effects of the space environment on the health and safety of space workers

Large numbers of individuals are required to work in space to assemble and operate a Solar Power Satellite. The physiological and behavioral consequences for large groups of men and women who perform complex tasks in the vehicular or extravehicular environments over long periods of orbital stay time were considered. The most disturbing consequences of exposure to the null gravity environment found relate to: (1) a generalized cardiovascular deconditioning along with loss of a significant amount of body fluid volume; (2) loss of bone minerals and muscle mass; and (3) degraded performance of neutral mechanisms which govern equilibrium and spatial orientation.

Hull, W. E.↗
NASA NTRS1982

Biomedical research publications: 1980 - 1982

Publications concerning the major physiological and psychological problems encountered by man when he undertakes space flight are listed. Nine research areas are included: cardiovascular deconditioning, motion sickness, bone alterations, muscle atrophy, blood cell alterations, fluid and eletrolyte changes, radiation effects and protection, behavior and performance, and general biomedical research.

Pleasant, L. G.↗
NASA NTRS1982

Spacelab mission 2: Experimental descriptions

The second Spacelab Mission and the 12 multidisciplinary experiments selected to fly on board are described. These experiments include the following: vitamin D metabolities and bone demineralization; interaction of oxygen and gravity influenced lignification; ejectable plasma diagnostics package; plasma depletion experiments for ionospheric and radio astronomical studies; small helium cooled IR telescope; elemental composition and energy spectra of cosmic ray nuclei; hard X-ray imaging of clusters of galaxies and other extended X-ray sources; solar magnetic and velocity field measurement system; solar coronal helium abundance Spacelab experiment; solar UV high resolution telescope and spectroraph; solar UV spectral irradiance monitor; and properties of superfluid helium in zero-G.

Clifton, K. S.↗
NASA NTRS1981

U.S. biological experiments in space

The history of biologic experimentation in space is traced. Early balloon and rocket borne animals showed no abnormalities on the macroscale, and biosatellite launches with bacteria and amoebae revealed no microscopic dysfunctions. Adult Drosophila flies on board Cosmos spacecraft died with a shortened lifespan, while their offspring lived full lifespans. Green pepper plants grown in weightlessness showed a different orientation, but no physiological disturbances. Normal bone growth in rats has been found to almost cease after 11 days in space, and the mean life span of red blood cells decreases by four days. A series of experiments designed by U.S. scientists will be performed on primates provided and flown by the U.S.S.R. Finally, experiments on board Spacelab will involve determination of the persistence of circadian rhythms in bacteria and humans.

Klein, H. P.↗
NASA NTRS1981

An overview of the endocrine and metabolic changes in manned space flight

Analyses of endocrinological and metabolic data from humans during spaceflight, particularly the Skylab crews, are summarized to define the levels of knowledge of these processes and the techniques for studying them. The glomerular filtration rate was tested by urine and blood samples, yielding indications of a creatinine clearance increase. The mechanisms for an increase of free water clearance, implying an increase of antidiuretic hormone, are uncertain, and tests are also under way to evaluate the role of prostaglandins in-flight, to account for decreases in catecholamine excretion. Bone mineral losses of 7.9% were observed at the end of 84 days, and processes are suggested for the calcium metabolism. Finally, the observation of almost universal weight loss among space crewmembers is examined, and a loss of muscle tone due to decreased metabolic efficiency is cited as a feature of long duration spaceflight.

Leach, C. S.↗
NASA NTRS1982

Skeletal abnormalities in rats induced by simulated weightlessness

A hypokinetic model has been developed which attempts to simulate the weightlessness experienced during space flight. Male rats were suspended from the model with a head-down tilt for a two-week period. Total mechanical unloading of the hind limbs and partial unloading of the fore limbs occurred. In comparison to pair-fed control rats, the skeletal alterations in the proximal tibial and humeral metaphyses of suspended rats were determined to be a diminished rate of longitudinal bone growth, a reduced mass of mineralized tissue, and an accumulation of marrow fat. Also, suspended rats exhibited decreased numbers of osteoblasts and increased numbers of osteoclasts immediately adjacent to the growth plate-metaphyseal junction at both skeletal sites. Although the reduction in mineralized tissue and the fat accumulation were more marked in the tibia, the skeletal changes in the proximal tibial and humeral metaphyses were generally comparable. The observed abnormalities may be due to mechanical unloading and/or a hypersecretion of corticosteroids.

Wronski, T. J.↗
NASA NTRS1982

Cardiovascular responses to weightlessness and ground-based simulations

Mission experience, from NASA and Soviet programs, on human cardiovascular responses to weightlessness, and the ability of bed rest studies to simulate these are discussed. In-flight effects include fluid shift to the upper body, decreased heart size, bone demineralization, orthostatic intolerance, and loss of exercise tolerance. All the cardiovascular changes that occur with weightlessness also occur with prolonged bed rest. They are most manifest when subjects stand suddenly, or undergo tilting or lower body negative pressure. The mechanisms which control these responses, e.g., the role of the central nervous system, are unclear.

Sandler, H.↗
NASA NTRS1982

Comparison between the weightlessness syndrome and aging

The similarity of detrimental effects of normal aging and of exposure to space weightlessness is discussed. The effects include: the reduction in cardiac output, increase in blood pressure, decrease in respiratory vital capacity, decrease in lean body weight and muscle mass, collagen and fat infiltration of muscle, bone demineralization, and a decrease in urinary excretion of total 17-hydroxicorticosteroids. It is also noted that dispite the accelerated aging of organisms, if animals or human subjects were to spend their entire lives in weightlessness, their lifespans might be significantly increased because of a reduction in metabolic rate. Experimental results are cited.

Miquel, J.↗
NASA NTRS1982

Human homeostasis in the space environment: A systems synthesis approach

The features of homeostatic changes which occur during adaptation to the weightless state are examined and the possible mechanisms underlying the responses are explored. Cardiac output, negative fluid balance, body weight, bone calcium, and muscle atrophy are discussed. Some testable hypotheses concerning possible effects on homeostasis that long-term exposure to weightlessness might cause are proposed.

Economos, A. C.↗
NASA NTRS1982

Aging and space travel

The matter of aging and its relation to space vehicle crewmembers undertaking prolonged space missions is addressed. The capabilities of the older space traveler to recover from bone demineralization and muscle atrophy are discussed. Certain advantages of the older person are noted, for example, a greater tolerance of monotony and repetitious activities. Additional parameters are delineated including the cardiovascular system, the reproductive system, ionizing radiation, performance, and group dynamics.

Mohler, S. R.↗
NASA NTRS1981

Some considerations in low-cost image processing on a university main frame: The Penn State (ORSER) experience

The ORSER System as implemented on the Penn State University Computation Center's IBM main frame is an exceptionally useful mechanism for instructing the present and future remote sensing community in the theory and practice of automated analysis of digitized data. From its beginning, the system was used as the hands-on back-bone of a graduate level "Multispectral Remote Sensing" one-term course taught annually in the School of Forest Resources. It was also used at the end of a senior-level undergraduate "Introduction to Remote Sensing" course, and in teaching a variety of short courses, ranging in length from a few days for small groups of remote sensing consultants with specific application interests, to a 2-week course oganized by NASA for regional and urban planners who had little or no previous exposure to remote sensing. Because of its modular construction, the ORSER is suitable for all classes of remote sensing users. Although in a beginning course only 6 to 10 of the programs are generally used, the researcher has a set of about 35 programs available for his analyses.

Turner, B. J.↗
NASA NTRS1983

Biomedical research publications, 1982 - 1983

Cardiovascular deconditioning, motion sickness, bone alterations, muscle atrophy, blood cell alterations, fluid and electrolyte changes, radiation effects and protection, behavior and performance, and general biomedical research are covered in a bibliography of 444 items.

Bolcik, C.↗
NASA NTRS1982

Evaluation of the response of rat skeletal muscle to a model of weightlessness

Suspension of rats in a head-down tilt position such that their hind limbs are non-load bearing has been proposed as a model for weightlessness. Changes observed in metabolism, bone formation (Morey et al., 1979), and muscle catabolism (Mussachia et al., 1980) support the validity of the model. To further document this model, the effects of suspension on the mechanical, biochemical and histochemical characteristics of two hind limb skeletal muscles, the gastrocnemius and the soleus, are investigated.

Templeton, G. H.↗
NASA NTRS1982

Metabolic experiments on Spacelab-4

Studies of human metabolism are being considered in five experiments. These investigations address physiological effects of zero gravity which have become evident in previous manned space flights, namely, negative Na, Ca and N balances, the resorption of bone, loss of red cell mass, cephalad migration of body fluids, and a shift in water balance. Although these effects have been fairly well established by pre- and postflight measurements, details of the mechanism by which they occur remain largely unknown. Moreover, the data collected inflight, particularly during the first few hours of weightlessness, have been severely limited both in the amount of quantitative information obtained and with respect to the relative simplicity of the experimental techniques employed. During the Spacelab 4 mission, the acute stage of the response to zero gravity will be the main focus of attention of several experiments. Measurements conducted later in the mission will center on the adaptive phase of metabolic responses.

Leach, C. S.↗
NASA NTRS1983

Gravity and the cells of gravity receptors in mammals

A model of the mammalian gravity receptor system is presented, with attention given to the effects of weightlessness. Two receptors are on each side of the head, with end organs in the saccule and utricle of the vestibular membranous labyrinth of the inner ear, embedded in the temporal bone. Each end organ has a macula, containing hair cells and supporting cells, and an otoconial complex, an otoconial membrane and mineral masses called otoconia. X ray powder diffraction examinations have revealed that the otoconia can behave like crystals, i.e., with piezoelectric properties, due to the mineral deposits. Bending of the hair cells because of acceleration can put pressure on the otoconial mineral, producing an electrical signal in the absence of a gravitational field. The possibility that pyroelectricity, as well as piezoelectricity, is present in the otoconial complexes, is discussed.

Ross, M. D.↗
NASA NTRS1983

Effects of weightlessness on body composition in the rat

The effects of weightlessness on the body composition of rats were investigated using 5 male rats exposed to 18.5 days of weightlessness on the COSMOS 1129 biosatellite and killed after reentry. The animals were immediately dissected and the three major body divisions (musculoskeletal system, skin, and pooled viscera) were analyzed for fat, water, solids, and six elements. These results were determined as percentages of the fat-free body or its components and then compared with two groups of terrestrial controls, one of which was subjected to a flight simulation in a spacecraft mock-up while the other was under standard vivarium conditions. Compared with the control groups, the flight group was found to exhibit a reduced fraction of total body water, a net shift of body water from skin to viscera, a marked diminution in the fraction of extracellular water in the fat-free body, a marked reduction in the fraction of bone mineral, no change in the quantity of stored fat or adrenal masses, and a net increase in total muscle mass as indicated by total body creatine, protein, and body cell mass.

Pitts, G. C.↗