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At least 55 records · Page 3Linked to original sources
PubMed1998

Neurobiological problems in long-term deep space flights.

Future missions in space may involve long-term travel beyond the magnetic field of the Earth, subjecting astronauts to radiation hazards posed by solar flares and galactic cosmic rays, altered gravitation fields and physiological stress. Thus, it is critical to determine if there will be any reversible or irreversible, detrimental neurological effects from this prolonged exposure to space. A question of particular importance focuses on the long-term effects of the space environment on the central nervous system (CNS) neuroplasticity, with the potential acute and/or delayed effects that such perturbations might entail. Although the short-term effects of microgravity on neural control were studied on previous low earth orbit missions, the late consequences of stress in space, microgravity and space radiation have not been addressed sufficiently at the molecular, cellular and tissue levels. The possibility that space flight factors can interact influencing the neuroplastic response in the CNS looms critical issue not only to understand the ontogeny of the CNS and its functional integrity, but also, ultimately the performance of astronauts in extended space forays. The purpose of this paper is to review the neurobiological modifications that occur in the CNS exposed to the space environment, and its potential consequences for extended deep space flight.

Adaptation, Physiological↗
PubMed2002

Space flight and oxidative stress.

Space flight is associated with an increase in oxidative stress after return to 1g. The effect is more pronounced after long-duration space flight. The effects lasts for several weeks after landing. In humans there is increased lipid peroxidation in erythrocyte membranes, reduction in some blood antioxidants, and increased urinary excretion of 8-iso-prostaglandin F(2alpha) and 8-oxo-7,8 dihydro-2 deoxyguanosine. Isoprostane 8-iso-prostaglandin F(2alpha) and 8-oxo-7,8 dihydro-2 deoxyguanosine are markers for oxidative damage to lipids and DNA, respectively. The changes have been attributed to a combination of the energy deficiency that occurs during flight and substrate competition for amino acids occurring between repleting muscle and other tissues during the recovery phase. The observations in humans have been complemented by rodent studies. Most rodent studies showed increased production of lipid peroxidation products postflight and decreased antioxidant enzyme activity postflight. The rodent observations were attributed to the stress associated with reentry into Earth's gravity. Decreasing the imbalance between the production of endogenous oxidant defenses and oxidant production by increasing the supply of dietary antioxidants may lessen the severity of the postflight increase in oxidative stress.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed2003

[Space flight and peroxidative damage].

Space flight is associated with an increase of peroxidative damage after returning to 1 g. The effect is more pronounced after long-duration space flight and can even last for several weeks after landing. In humans there is increased lipid peroxidation in erythrocyte membranes, reduced blood antioxidants, and increased urinary excretion of 8-iso-prostaglandin F2alpha, and 8-oxo-7, 8 dihydro-2 deoxyguanosine. Isoprostane 8-iso-prostaglandin F2alpha and 8-oxo-7, 8 dihydro-2 deoxyguanosine are markers for oxidative damage to lipids and DNA, respectively. The changes are attributed to a combination of energy deficiency that occurs during flight and substrate competition for amino acids occurring between repleted muscle and other tissues during the recovery phase. The observations in humans have been complemented by studies in rodents, which showed increased production of lipid peroxidation products and decreased antioxidant enzyme activity afterflight. The changes in rodents were attributed to the stress associated with re-entry into Earth's gravity. Reducing the imbalance between the production of endogenous oxidant defenses and oxidant production by increasing the supply antioxidants in diet may lessen the severity of the postflight increase in oxidative stress.

Animals↗
PubMedDate not supplied

[Free course of circadian rhythms in Trigonoscelis gigas beetles after space flight].

Before and after space flight on Cosmos-1887 motor activity of Trigonoscelis gigas beetles kept in darkness was recorded. After flight 6 out of 7 beetles showed reduction of periods of free running circadian rhythms. The fact that the change was not observed in controls suggests that it can be attributed to the effects of O G. It is assumed that in space flight the biological requirements for the day duration are modified.

Animals↗
PubMed1993

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.

Action Potentials↗
PubMed2003

[Effects of microgravity on human cognitive function in space flight].

In researches of space flight, studies on the effects of microgravity on cognitive function were relatively few. This paper reviews recent progress on this topic. It was shown that under the condition of microgravity, spatial orientation, motion perception and early process of object recognition were impaired to a certain degree. Capability of muscle movement and coordination was lowered, while higher cognitive functions, such as logic reasoning task, the speed and accuracy of short-term memory retrieval were less affected by microgravity. But long-term memory tasks and performance in which attention processes were needed (e.g., tracking task, selective response task), were impaired during space flight or under simulated weightlessness condition.

Cognition↗
PubMed2000

[Changes in productivity of plant cells as result of cultivation under the space flight conditions].

Effects of space flight on growth and biosynthetic features of plant cells were studied in two strains of ginseng (Panax ginseng) differing in growth and particularly biosynthetic activities, a strain of Lithospermum Erythrorhizon and a strain of Macrotomia Euchroma which produce biologically active naphroquin-derived pigments. --and also differ in growth and biosynthetic properties. Following exposure aboard MIR and a Space shuttle, cells of the callosal cultures were subjected to callosal or suspension passaging. Biomass yield and biologically active substances--ginseng saponins ginsenoids and shikonin were determined in the cells cultures. There was no evidence for the biomass yield to be significantly altered by space flight; however, the content of biologically active substances was materially changed with the strain.

Extraterrestrial Environment↗
PubMed2003

Characteristic of changes in the structure and metabolism of the vastus lateralis muscles in monkeys after space flight.

Monkeys subjected to space flight were found to have significant decreases in the sizes of slow and rapid fibers in the vastus lateralis muscle, due not only to weightlessness but also, to some extent, to restriction of movement activity within the capsule. The quantity of total protein in muscle fibers did not decrease. The respiratory peak in the pool of vastus lateralis muscle fibers decreased after space flight, as did the activity of oxidative enzymes (particularly in rapid fibers of the vastus lateralis muscle).

Animals↗
PubMed2000

[Ultraviolet radiation and long term space flight].

With the prolongation of space flight, influences of various aerospace environmental factors on the astronauts become more and more severe, while ultraviolet radiation is lacking. Some studies indicated that low doses of ultraviolet rays are useful and essential for human body. In space flight, ultraviolet rays can improve the hygienic condition in the space cabin, enhance astronaut's working ability and resistance to unfavorable factors, prevent mineral metabolic disorders, cure purulent skin diseases and deallergize the allergens. So in long-term space flight, moderate amount of ultraviolet rays in the space cabin would be beneficial.

Aerospace Medicine↗
PubMed2003

The response of endocrine system to stress loads during space flight in human subject.

The responses of endocrine system to the exposure to stress-work load and hormonal changes during oral glucose tolerance tests were studied in the Slovak astronaut before (three weeks before flight), during (on the 4th and the 6th days of space flight), and after space flight (1-3 days and 15-17 days after space flight) on board of space station MIR. Blood samples during the tests were collected via cannula inserted into cubital vein, centrifuged in the special appliance Plasma-03, frozen in Kryogem-03, and at the end of the 8-day space flight transferred to Earth in special container for hormonal analysis. Preflight workload produced an increase of plasma norepinephrine and a moderate elevation of epinephrine levels. Plasma levels of insulin, growth hormone, prolactin and cortisol were not markedly changed immediately or 10 min after the end of work load. The higher increases of plasma growth hormone, prolactin and catecholamine levels were noted after workload during space flight as compared to preflight response. The higher plasma glucose and insulin levels were noted during the oral glucose tolerance test in space flight and also in the post flight period. Plasma epinephrine levels were slightly decreasing during glucose tolerance test; however, plasma norepinephrine levels were not changed. The similar patterns of catecholamine levels during glucose tolerance test were found when compared the preflight, in-flight and post flight values. These data demonstrate the changes of the dynamic responses of endocrine system to stress-work and metabolic loads during space flight in human subject.

Adaptation, Physiological↗
PubMed1991

Oculomotor function during space flight and susceptibility to space motion sickness.

Horizontal vestibulo-ocular reflex (VOR) and saccadic eye movements (SEM) were studied in 18 subjects before and during five Space Shuttle missions to evaluate the effects of weightlessness and correlations between results and susceptibility to and actual presence of space motion sickness (SMS). Active sinusoidal head oscillation was the stimulus for VOR tests with vision (VVOR), with eyes shaded (VOR-ES), and VOR suppression (VOR-S). Eye movements were recorded by electrooculography and head position by a potentiometer. No pathological nystagmus or other abnormal eye movements were seen. No significant in-flight changes were seen in the gain, phase shift or waveform of VVOR, VOR-ES, or VOR-S. Statistically significant increases in saccadic latency and decreases in saccadic velocity were seen, with no change in saccadic accuracy. Preflight differences between SMS susceptible and non-susceptible subjects were noted only in VOR-S, with less complete suppression in susceptible subjects, a finding also seen in flight. During flight, VVOR gain was significantly increased in three non-affected subjects. Saccades of SMS-affected subjects showed increased latency and velocity and decreased accuracy compared to saccades of unaffected subjects.

Adult↗
PubMed1980

Male and female characteristics in vestibular testing: a step toward the selection of the best participants for space flight.

Vestibular disturbances in connection with space flight were reported by a majority of participating astronauts and cosmonauts. These include motion sickness symptoms in the first few days of the space flight, as well as standing, gait and orientation disturbances after the return to Earth. The Aerospace Medical Community has been trying to select those people that are particularly adapted to the above stresses or that can be further adapted through training programs. As the circle of selectees extends to women, the problem arises as to whether differences between men and women exist under the conditions of space flight. In seeking answers to this question we studied a group of 42 women and 44 men, who were further subdivided according to their subjective motion sickness sensitivity, as determined by a questionnaire. Using this material, 26 men and 22 women were designated as motion sickness resistant, and 18 men and 20 women were designated as nonresistant. The vestibular test battery given these test subjects consisted of caloric, rotatory, optokinetic, vestibulo-spinal and vestibulo-vegetative testing. Because of the mixed orthostatic and vestibular problems seen after space flights, we also studied the response of the vestibular apparatus during peripheral blood pooling as induced by lower body negative pressure. The collected historical and test data are analyzed in this paper with emphasis on the relationship to motion sickness tendency.

Aerospace Medicine↗
PubMed2002

Insulin secretion and sensitivity in space flight: diabetogenic effects.

Nearly three decades of space flight research have suggested that there are subclinical diabetogenic changes that occur in microgravity. Alterations in insulin secretion, insulin sensitivity, glucose tolerance, and metabolism of protein and amino acids support the hypothesis that insulin plays an essential role in the maintenance of muscle mass in extended-duration space flight. Experiments in flight and after flight and ground-based bedrest studies have associated microgravity and its experimental paradigms with manifestations similar to those of diabetes, physical inactivity, and aging. We propose that these manifestations are characterized best by an etiology that falls into the clinical category of "other" causes of diabetes, including, but not restricted to, genetic beta-cell defects, insulin action defects, diseases of the endocrine pancreas, endocrinopathies, drug or chemically induced diabetes, infections, immune-mediated metabolic alteration, and a host of genetic related diseases. We present data showing alterations in tumor necrosis factor-alpha production, insulin secretion, and amino acid metabolism in pancreatic islets of Langerhans cultured in a ground-based cell culture bioreactor that mimics some of the effects of microgravity. Taken together, space flight research, ground-based studies, and bioreactor studies of pancreatic islets of Langerhans support the hypothesis that the pancreas is unable to overcome peripheral insulin resistance and amino acid dysregulation during space flight. We propose that measures of insulin secretion and insulin action will be necessary to design effective countermeasures against muscle loss, and we advance the "disposition index" as an essential model to be used in the clinical management of space flight-induced muscle loss.

Amino Acids↗
PubMed1997

Effects of space flight on ovarian-hypophyseal function in postpartum rats.

The effect of space flight in a National Aeronautics and Space Administration (NASA) shuttle was studied in pregnant rats. Rats were launched on day 9 of gestation and recovered on day 20 of gestation. On day 20 of gestation, rats were unilaterally hysterectomized and subsequently allowed to go to term and deliver vaginally. There was no effect of space flight on pituitary and ovary mass postpartum. In addition, space flight did not alter healthy and atretic ovarian antral follicle populations, fetal wastage in utero, plasma concentrations of progesterone and luteinizing hormone (LH) or pituitary content of follicle stimulating hormone (FSH). Space flight significantly increased plasma concentrations of FSH and decreased pituitary content of LH at the postpartum sampling time. Collectively, these data show that space flight, initiated during the postimplantation period of pregnancy, and concluded before parturition, is compatible with maintenance of pregnancy and has minimal effects on postpartum hypophyseal parameters; however, none of the ovarian parameters examined was altered by space flight.

Animals↗
PubMed2003

[Application prospect of human-artificial intelligence system in future manned space flight].

OBJECTIVE: To make the manned space flight more efficient and safer, a concept of human-artificial (AI) system is proposed in the present paper. METHOD: The task of future manned space flight and the technique requirement with respect to the human-AI system development were analyzed. RESULT: The main points are as follows: 1)Astronaut and AI are complementary to each other functionally; 2) Both symbol AI and connectionist AI should be included in the human-AI system, but expert system and Soar-like system are used mainly inside the cabin, the COG-like robots are mainly assigned for EVA either in LEO flight or on the surface of Moon or Mars; 3) The human-AI system is hierarchical in nature with astronaut at the top level; 4) The complex interfaces between astronaut and AI are the key points for running the system reliably and efficiently. CONCLUSION: As the importance of human-AI system in future manned space flight and the complexity of related technology, it is suggested that the R/D should be planned as early as possible.

Artificial Intelligence↗
PubMedDate not supplied

Evaluation of NASA Foodbars as a standard diet for use in short-term rodent space flight studies.

OBJECTIVES: [corrected] A standard rodent diet for space flight must meet the unique conditions imposed by the space environment and must be nutritionally adequate because diet can influence the outcome of experiments. We evaluated the use of National Aeronautics and Space Administration (NASA) Foodbars as a standard space flight diet for rats. METHODS: The Foodbar's semi-purified formulation permitted criteria such as nutrient consistency, high nutrient bioavailability, and flexibility of formulation to be met. Extrusion of the semi-purified diet produced Foodbars with the proper texture and a non-crumbing solid form for use in space. Treatment of Foodbar with 0.1% potassium sorbate prevented mold growth. Irradiation (15 to 25 kGy) prevented bacterial growth and, in combination with sorbate treatment, added protection against mold for shelf stability. RESULTS: During the development process, nutrient analyses indicated that extrusion and irradiation produces nutrient losses. Nutrients were adjusted accordingly to compensate for processing losses. Nutrient analysis of Foodbars continues to be performed routinely to monitor nutrient levels. It is important that the standard rodent diet provide nutrients that will prevent deficiency but also avoid excess that may mask physiologic changes produced by space flight. All vitamin levels in the Foodbars, except for vitamin K, conformed to or exceeded the current National Research Council (NRC) 1995 recommendations. All indispensable amino acids in Foodbar conformed to or exceeded the NRC nutrient recommendation for mouse growth and rat maintenance. However, some indispensable amino acids were slightly below recommendations for rat reproduction and growth. Short-term (18 to 20 d) animal feeding studies indicated that Foodbars are palatable, support growth, and maintain health in rats. CONCLUSIONS: Results indicated that NASA Rodent Foodbars meet the physical and nutritional criteria required to support rodents in the space environment and thus may be used successfully as a standard diet for short-term space flight studies. However, the nutritional adequacy of NASA Rodent Foodbars as a standard diet on longer-duration (>20 d) space flight missions remains to be determined.

Amino Acids↗