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PubMed1997

[Space required for sheep during transport].

Space required for different body, positions was investigated for sheep of different weight and genetic background in undisturbed housing conditions. Body temperature, as stress indicator, was measured at different intervals during transport. The loading situation caused a distinct increase; a slight increase was measured after unloading. During transport, the values did not reach those taken before loading. Concerning the space required for resting, the present results indicate that sheep (weighing between 32 and 35 kg) being transported with a space allowance of 0.16, 0.26, 0.27, 0.42 and 0.45 m2/animal showed an appreciable amount of resting behaviour only at lower densities, i.e. with space allowance of more than 0.40 m2. The recommended space allowance by the EU of 0.21 to 0.23 m2 for sheep of this weight group has to be considered as too low to permit effective resting behaviour. The problem of supplying sheep with water and feed during transport has not yet been solved. The question is not only how much space the animals need for feeding but also a matter of the technical equipment for supplying feed and water so that all animals are able to reach it.

Animal Husbandry↗
PubMed1998

Space changes after premature loss of the mandibular primary first molar: a longitudinal study.

The purpose of this study was to evaluate the space changes after premature loss of the primary mandibular first molar. Twenty-one children (12 boys and 9 girls), with premature loss of the primary mandibular first molar, were selected from the children's dental clinic for this study. The age ranged from 5.1 to 7.2 years with an average of 6 years and 11 months. Mandibular study casts were made from alginate impression for each initial examination and a follow-up examination eight months later. Four measurements including D+E (first and second primary molars) space, arch width, arch length and arch perimeter were tested for comparisons between the initial examination and the follow-up examination eight months later. The D+E space of intact primary molars served as a control. The results showed that the D+E space on the extraction side after the follow-up examination eight months later was significantly shorter than the control side (p = 0.025) and less than the initial D+E space (p < 0.001). However, there were no significant differences on arch width, arch length, and arch perimeter between the initial examination and the follow-up examination eight months later (p > 0.05). It is concluded that the space change after the eruption of the first permanent molar in the mandible is mostly distal movement of the primary cuspid during the early stage of premature loss of the primary first molar.

Child↗
PubMed2000

Cell science and protein crystal growth research for the International Space Station.

The recent National Research Council report, Future Biotechnology Research on the International Space Station, evaluates NASA's plans for research in cell science and protein crystal growth to be conducted on the International Space Station. This report concludes that the NASA biotechnology programs have the potential to significantly impact relevant scientific fields and to increase understanding and insight into fundamental biological issues. In order to realize the potential impacts, NASA must focus its research programs by selecting specific questions related to gravitational forces' role in cell behavior and by using the microgravity environment as a tool to determine the structure of macromolecules with important biological implications. Given the time and volume constraints associated with space-based experiments, instrumentation to be used on the space station must be designed to maximize the productivity of researchers, and NASA's recruitment of investigators and support for space station experiments should aim to encourage and facilitate cutting-edge research.

Biotechnology↗
PubMed1997

Altered astronaut lower limb and mass center kinematics in downward jumping following space flight.

Astronauts exposed to the microgravity conditions encountered during space flight exhibit postural and gait instabilities upon return to earth that could impair critical postflight performance. The aim of the present study was to determine the effects of microgravity exposure on astronauts' performance of two-footed jump landings. Nine astronauts from several Space Shuttle missions were tested both preflight and postflight with a series of voluntary, two-footed downward hops from a 30-cm-high step. A video-based, three-dimensional motion-analysis system permitted calculation of body segment positions and joint angular displacements. Phase-plane plots of knee, hip, and ankle angular velocities compared with the corresponding joint angles were used to describe the lower limb kinematics during jump landings. The position of the whole-body center of mass (COM) was also estimated in the sagittal plane using an eight-segment body model. Four of nine subjects exhibited expanded phase-plane portraits postflight, with significant increases in peak joint flexion angles and flexion rates following space flight. In contrast, two subjects showed significant contractions of their phase-plane portraits postflight and three subjects showed insignificant overall changes after space flight. Analysis of the vertical COM motion generally supported the joint angle results. Subjects with expanded joint angle phase-plane portraits postflight exhibited larger downward deviations of the COM and longer times from impact to peak deflection, as well as lower upward recovery velocities. Subjects with postflight joint angle phase-plane contraction demonstrated opposite effects in the COM motion. The joint kinematics results indicated the existence of two contrasting response modes due to microgravity exposure. Most subjects exhibited "compliant" impact absorption postflight, consistent with decreased limb stiffness and damping, and a reduction in the bandwidth of the postural control system. Fewer subjects showed "stiff" behavior after space flight, where contractions in the phase-plane portraits pointed to an increase in control bandwidth. The changes appeared to result from adaptive modifications in the control of lower limb impedance. A simple 2nd-order model of the vertical COM motion indicated that changes in the effective vertical stiffness of the legs can predict key features of the postflight performance. Compliant responses may reflect inflight adaptation due to altered demands on the postural control system in microgravity, while stiff behavior may result from overcompensation postflight for the presumed reduction in limb stiffness inflight.

Acceleration↗
PubMed2005

Contribution of reference frames for movement planning in peripersonal space representation.

The principal goal of our study is to gain an insight into the representation of peripersonal space. Two different experiments were conducted in this study. In the first experiment, subjects were asked to represent principal anatomical reference planes by drawing ellipses in the sagittal, frontal and horizontal planes. The three-dimensional hand-drawing movements, which were achieved with and without visual guidance, were considered as the expression of a cognitive process per se: the peripersonal space representation for action. We measured errors in the spatial orientation of ellipses with regard to the requested reference planes. For ellipses drawn without visual guidance, with eyes open and eyes closed, orientation errors were related to the reference planes. Errors were minimal for sagittal and maximal for horizontal plane. These disparities in errors were considerably reduced when subjects drew using a visual guide. These findings imply that different planes are centrally represented, and are characterized, by different errors when subjects use a body-centered frame for performing the movement and suggest that the representation of peripersonal space may be anisotropic. However, this representation can be modified when subjects use an environment-centered reference frame to produce the movement. In the second experiment, subjects were instructed to represent, with eyes open and eyes closed, sagittal, frontal and horizontal planes by pointing to virtual targets located in these planes. Disparities in orientation errors measured for pointing were similar to those found for drawing, implying that the sensorimotor representation of reference planes was not constrained by the type of motor tasks. Moreover, arm postures measured at pointing endpoints and at comparable spatial locations in drawing are strongly correlated. These results suggest that similar patterns of errors and arm posture correlation, for drawing and pointing, can be the consequence of using a common space representation and reference frame. These findings are consistent with the assumption of an anisotropic action-related representation of peripersonal space when the movement is performed in a body-centered frame.

Adult↗
PubMed1999

Technical note: a new model for quantitative analysis of brain oedema resolution into the ventricles and the subarachnoid space.

OBJECTIVE: The aim of the current study was to develop an experimental animal model for quantitative analysis of oedema resolution via the subarachnoid space and the ventricular system using fluorescent oedema markers. METHODS: Artificial cerebrospinal fluid (CSF) containing TRITC-albumin (MW 67.000D) and Na(+)-fluorescein (MW 376D) was continuously infused into the white matter of the left frontal lobe of New Zealand white rabbits (n = 6) at a rate of 100 microliters/h for 3 hrs. A closed cranial window for superfusion of the brain surface with artificial CSF fluid (3 ml/h) was implanted above the left parietal cortex for measurement of the fluorescence markers in the subarachnoid space. Uptake of the fluorescence indicators into the ventricles was quantified by ventriculo-cisternal perfusion (3 ml/h). The effluates were collected at 30 min intervals for 3 hrs after the start of infusion. Clearance of the oedema fluid into the perfusates was measured by fluorescence spectrophotometry. RESULTS: At an intracranial pressure of 15.0 +/- 1.7 mm Hg (mean +/- SEM) both indicators started to accumulate in the subarachnoid and ventricular perfusates at 90 min following onset of oedema fluid infusion. The concentrations of the indicators in the ventricular system increased to 7.7 +/- 5.1% of Na(+)-fluorescein and 16.1 +/- 13.0% of TRITC-albumin of the total amount infused were recovered in the ventricular system at 3 hours after start of the oedema infusion, while 3.4 +/- 3.2% of Na(+)-fluorescein and 3.7% +/- 3.2 of TRITC-albumin, respectively, were found in the effluates of the subarachnoid space. CONCLUSION: The present study demonstrates that resolution of vasogenic brain oedema into the cerebral ventricular system and the subarachnoid space following its entry into cerebral white matter can be quantitatively analysed using fluorescence markers, which serve as oedema fluid indicators. The results indicate that the oedema fluid is cleared not only into the ventricular system but also via the subarachnoid space.

Animals↗
PubMedDate not supplied

U.S. manned space flight: the first twenty years, a biomedical status report.

In the last 20 years, the biomedical problems facing man in space have been brought into sharper focus. Space motion sickness is presently our most serious problem. Its etiology remains obscure, but the "sensory conflict" theory appears most plausible. No valid predictive tests of susceptibility exist and presently we must rely on medication for prevention or mitigation of symptoms. Adaptation/biofeedback techniques may prove useful. Cardiovascular "deconditioning" may be effectively attenuated by use of anti-g suits or plasma expanding techniques. Recent bedrest simulation studies would seem to indicate that concerns about chronically elevated central venous pressure during space flight are unfounded. The loss of red cell mass in space flight appears to be self-limited, independent of mission duration, and not of clinical concern, based on recent Soviet experiences. And finally, clodronate, a new diphosphonate effective in preventing hypercalciuria and negative calcium balance in normal human bedrested subjects, may prove effective in preventing or lessening skeletal mineral loss in space.

Adaptation, Physiological↗
PubMed1992

Development of life support requirements for long-term space flight.

When humans move out into the solar system to stay for long durations, the most immediate challenge will be the provision of a life-supporting environment in locations that are naturally devoid of food, air, and water. Life support systems must provide these commodities in all phases of space flight--during intravehicular activity (IVA) and during extra-vehicle activity (EVA). Systems that support human life must provide: overall reliability in the space environment, allowing maintenance and component replacement in space; reduced resupply mass of consumables and spares; for planetary surfaces, the ability to utilize local resources for increased self sufficiency; and the minimized mass power and volume requirements necessary for all space flight systems. This paper will discuss the melding of these technical requirements in such a way as to meet the human needs of space flight.

Ecological Systems, Closed↗
PubMed2004

Structural changes in glutamate cell swelling followed by multiparametric q-space diffusion MR of excised rat spinal cord.

Diffusion in the extracellular and intracellular spaces (ECS and ICS, respectively) was evaluated in excised spinal cords, before and after cell swelling induced by glutamate, by high b-value q-space diffusion MR of specific markers and water. The signal decays of deuterated tetramethylammonium (TMA-d(12)) chloride, an exogenous marker of the ECS, and N-acetyl aspartate (NAA), an endogenous marker of the ICS, were found to be non-mono-exponential at all diffusion times. The signal decays of these markers were found to depend on the diffusion time and the cell swelling induced by the glutamate. It was found, for example, that the mean displacements of the apparent fast and slow diffusion components of TMA-d(12) are 7.21 +/- 0.11 and 1.16 +/- 0.05 microm, respectively at a diffusion time of 496 ms. After exposure of the spinal cords to 10 mM of glutamate, these values decreased to 6.62 +/- 0.13 and 1.01 +/- 0.05 microm, respectively. The mean displacement of NAA, however, showed a less pronounced opposite trend and increased after cell swelling induced by exposure to glutamate. q-Space diffusion MR of water was found to be sensitive to exposure to glutamate, and q-space diffusion MRI showed that a more pronounced decrease in the apparent diffusion coefficient and the mean displacement of water is observed in the gray matter (GM) of the spinal cord. All these changes demonstrate that diffusion MR is indeed sensitive to structural changes caused by cell swelling induced by glutamate. Multiparametric high b-value q-space diffusion MR is useful for obtaining microstructural information in neuronal tissues.

Animals↗
PubMed2000

Nurses' contributions to the US space program.

Nurses have been engaged in aspects of aviation and space endeavors from their beginnings. Although no nurse has been chosen as a potential astronaut, nurses have contributed to the space program in many ways. Nurses and other health care providers use technology adapted from the space program. The future of extended space flight remains unclear, although work continues on completing a space station for extended stays on the moon and trips to Mars. Nurses may be one of the health care team members on these excursions.

Adaptation, Physiological↗
PubMedDate not supplied

Main problems of the Russian Orlan-M space suit utilization for EVAs on the ISS.

In the recent years the Russian Orlan-M space suits have been improved as applied to their operational requirements for the ISS. A special attention is paid to enhancement of EVA crew efficiency and safety. The paper considers the main problems regarding specific features of the Russian space suit operation in the ISS, and analyses measures on their solution. In particular, the problems associated with the following are considered: enhancement of the anthropometric range for the EVA crewmembers; use of some US EMU elements and unified NASA equipment elements; Orlan-M operation support in the wide range of the ISS thermal conditions; use of Simplified Aid For Extravehicular activity Rescue (SAFER) designed as a self-rescue device, which will be used for an EVA crewmember return in the event that he (she) breaks away inadvertently from the ISS surface. The paper states the main space suit differences with reference to solution of the above problems. The paper presents briefly the design of space suit arms developed for crewmembers with small anthropometric parameters, as well as peculiarities and test results for the gloves with enhanced thermal protection. Measures on further space suit development with the purpose to improve its performances are considered.

Anthropometry↗
PubMedDate not supplied

Human interactions in space: results from Shuttle/Mir.

BACKGROUND: Anecdotal reports from space and results from simulation studies on Earth have suggested that space crewmembers may experience decrements in their interpersonal environment over time and may displace tension and dysphoria to mission control personnel. METHODS: To evaluate these issues, we studied 5 American astronauts, 8 Russian cosmonauts, and 42 American and 16 Russian mission control personnel who participated in the Shuttle/Mir space program. Subjects completed questions from subscales of the Profile of Mood States, the Group Environment Scale, and the Work Environment Scale on a weekly basis before, during, and after the missions. RESULTS: Among the crewmembers, there was little evidence for significant time effects based on triphasic (U-shaped) or linear models for the 21 subscales tested, although the presence of an initial novelty effect that declined over time was found in three subscales for the astronauts. Compared with work groups on Earth, the crewmembers reported less dysphoria and perceived their crew environment as more constraining, cohesive, and guided by leadership. There was no change in ratings of mood and interpersonal environment before, during, and after the missions. CONCLUSIONS: There was little support for the presence of a moderate to strong time effect that influenced the space crews. Crewmembers perceived their work environment differently from people on Earth, and they demonstrated equanimity in mood and group perceptions, both in space and on the ground. Grant numbers: NAS9-19411.

Adaptation, Psychological↗
PubMed2003

Studies toward birth and early mammalian development in space.

Sustaining life beyond Earth on either space stations or other planets will require a clear understanding of how the space environment affects key phases of mammalian reproduction and development. Pregnancy, parturition (birth) and the early development of offspring are complex processes essential for successful reproduction and the proliferation of mammalian species. While no mammal has yet undergone birth within the space environment, studies spanning the gravity continuum from 0- to 2-g are revealing startling insights into how reproduction and development may proceed under gravitational conditions deviating from those typically experienced on Earth. In this report, I review studies of pregnant Norway rats and their offspring flown in microgravity onboard the NASA Space Shuttle throughout the period corresponding to mid- to late gestation, and analogous studies of pregnant rats exposed to hypergravity (hg) onboard the NASA Ames Research Center 24-ft centrifuge. Studies of postnatal rats flown in space or exposed to centrifugation are reviewed. Although many important questions remain unanswered, the available data suggest that numerous aspects of pregnancy, birth and early mammalian development can proceed under altered gravity conditions.

Animals↗
PubMed2002

Water and energy dietary requirements and endocrinology of human space flight.

Fluid and energy metabolism and related endocrine changes have been studied nearly from the beginning of human space flight in association with short- and long-duration flights. Fluid and electrolyte nutrition status is affected by many factors including the microgravity environment, stress, changes in body composition, diet, exercise habits, sleep cycles, and ambient temperature and humidity conditions. Space flight exposes astronauts to all these factors and consequently poses significant challenges to establishing dietary water, sodium, potassium, and energy recommendations. The purpose of this article is to review the results of ground-based and space flight research studies that have led to current water, electrolyte, and energy dietary requirements for humans during space flight and to give an overview of related endocrinologic changes that have been observed in humans during short- and long-duration space flight.

Body Temperature Regulation↗
PubMed2003

The impact of the new biology on radiation risks in space.

Radiation is considered to be one of three or four major hazards for personnel in space and has emerged as the most critical issue to be resolved for long-term missions, both orbital and interplanetary. Space habitats are stressful and dangerous environments. Health and medical consequences arising from microgravity, stress, and trauma include weakened immune systems, increased viral activity, and loss of bone mass. The greatest risks from radiation are generally assumed to be cancers and possibly damage to the central nervous system. Synergistic effects arising from the other environmental hazards along with abscopal and exogenic factors are likely. Space programs represent an exceptional opportunity for examining the biological consequences of low-dose exposures of humans to radiation at every level of progression. Although astronauts are a relatively small population, they are healthy, physically active volunteers who undergo extensive testing and medical examinations before, during, and after protracted exposures with periodic follow-up examinations. The radiation environments along with other hazards are likewise monitored and documented. Extensive international research programs are in progress. Seven years ago the U.S. National Aeronautics and Space Administration established the National Space Biomedical Research Institute through a cooperative agreement with a consortium of research and academic institutions in order to address radiation issues through a concerted, programmatic effort. Advanced technologies are rapidly being incorporated into these programs to determine the significance of new biological data and to evaluate the interplay among the different medical hazards. Programmatic in vivo and in vitro studies of the processes leading to carcinogenesis are in progress. Drugs and dietary supplements are being examined at the cellular and in vivo levels to assess their potential as dose-modifying agents. The infrastructure of this new approach, recent results, and research in progress are reviewed and discussed.

Academies and Institutes↗
PubMed1990

Reproduction in the space environment: Part I. Animal reproductive studies.

Mankind's exploration and colonization of the frontier of space will ultimately depend on men's and women's ability to live, work, and reproduce in the space environment. This paper reviews animal studies, from microorganisms to mammals, done in space or under space-simulated conditions, which identify some of the key areas which might interfere with human reproductive physiology and/or embryonic development. Those space environmental factors which impacted almost all species included: microgravity, artificial gravity, radiation, and closed life support systems. These factors may act independently and in combination to produce their effects. To date, there have been no studies which have looked at the entire process of reproduction in any animal species. This type of investigation will be critical in understanding and preventing the problems which will affect human reproduction. Part II will discuss these problems directly as they relate to human physiology.

Animals↗
PubMed2001

The biomedical challenges of space flight.

Space medicine has evolved considerably through past U.S. missions. It has been proven that humans can live and work in space for long durations and that humans are integral to mission success. The space medicine program of the National Aeronautics and Space Administration (NASA) looks toward future long-duration missions. Its goal is to overcome the biomedical challenges associated with maintaining the safety, health, and optimum performance of astronauts and cosmonauts. This program investigates the health effects of adaptation to microgravity: the nature of their pathologies, the effects of microgravity on pathophysiology, and the alterations in pharmacodynamics and treatment. A critical capability in performing research is the monitoring of the health of all astronauts and of the spacecraft environment. These data support the evidence-based approach to space medicine, incorporating past studies of microgravity-related conditions and their terrestrial counterparts. This comprehensive approach will enable safe and effective exploration beyond low Earth orbit.

Adaptation, Physiological↗
PubMed1991

Waste management for Space Station Freedom.

Because of the tremendous task of designing, testing, building and maintaining the waste systems for Space Station Freedom, different methods of managing these systems are now being developed. This paper summarizes some of those methods. The first task for the design engineer is to develop systems and hardware to handle waste in the special conditions of the space station. Different closed and open loop systems, along with the development of new hardware in these loops, are being tested to meet this task. Some of the new hardware to be discussed are water and air monitors, hazardous material handling, and plumbing hardware such as commodes, showers and clothes washers. The second task is to develop methods to manage the process of developing these systems. Some of the areas to manage are testing information, materials, facilities, people, budgets, time, safety, legal responsibilities and testing standards. The last task is to incorporate the new technologies for other areas besides space stations. Other areas would include long-duration space missions, lunar stations and other non-space applications.

Ecological Systems, Closed↗