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At least 577 records · Page 32Linked to original sources
PubMed1975

Quantitative cyto- and histochemical studies of the Deiter's nucleus and nodular cortex of cerebellum in rats exposed to weightlessness.

Spaceflight aboard the "Cosmos-605" artificial satellite during 22 d does not have a substantial effect upon the activity of enzymes involved in energy metabolism--lactate dehydrogenase and creatine kinase--in cytoplasm of the giant neurons of the dorsocaudal part of the Deiters' nucleus and cortex layers of the cerebellar nodulus in rats. At the same time, on the second postflight day, in the molecular layer of cerebellar nodulus in rats flown for 22 d in space, some increase in lipid content was noted, probably connected with quantitative or qualitative changes in afferent impulses from the vestibular apparatus to the nodulus. On the 27th postflight day, lipid content in the molecular layer returned to the level observed in rats during ground-based experiments.

Animals↗
PubMed1972

OFO experimental techniques and preliminary conclusions: is artificial gravity needed during prolonged weightlessness?

The technique of single unit recording from body systems generating electrical pulses coherent with their basic function (CNS, muscles, sense organs) has been proved feasible during the OFO A orbital flight, an automatic physiological experiment. All microelectrode implants survived the lift off of a Scout vehicle. The far-reaching impact of such a technique in biological space research and in the laboratory is discussed. The results of recording 155 hours of orbital flight of pulses from the nerve fibres of four vestibular gravity sensors in two bull frogs indicate that the vestibular organ adjusts to zero g. As all the other biological changes observed during orbit are due to lack of exercise, it is concluded that artificial gravity might not be necessary during prolonged space missions or on low gravity celestial bodies.

Animals↗
PubMed1972

Effects of weightlessness on astronauts--a summary.

This paper reviews the adaptive changes observed in the United States astronauts during flight programs to this date. A series of postulates are offered as to what is happening in these adaptive events. A hypothesis is proposed as to the interrelationship of events observed in the body systems and functions involved. The importance of undertaking an extensive life sciences program. including an on-orbit phase of study as well as pre- and post-flight studies is discussed. Finally, the role the Skylab flight plays in the United States Space Program in achieving the future requirements for more extensive life sciences data is summarized.

Adaptation, Physiological↗
PubMed1976

Investigation of radiation sensitivity in mammals under long duration weightlessness.

Preliminary results of the radiobiological experiments carried out on the biosatellite Cosmos 690 with a radiation exposure unit on board are presented. The duration of the satellite flight was 20.5 days. On the tenth day of the flight 35 rats were exposed on board the satellite to 220 or 800 rads of gamma radiation. Comparison of data obtained in test and control groups of animals has shown that under the influence of space flight factors a somewhat more severe radiation injury develops than in on-ground conditions.

Animals↗
PubMed2002

[Structural-metabolic plasticity of mammalian skeletal muscles in hypokinesis and weightlessness].

Under review are investigations of the contractile structure of skeletal muscles of humans and animals (rats and primates) following space flight, long-term hypokinesia, immersion (human subjects) and head-down suspension (rats). Close consideration is given to experimental testing of hypotheses concerning neuronal, humoral and cell processes leading to atrophy. Described are consistencies and mechanisms of changes in the myosin phenotype and electromechanic coupling in muscular fibers as well as their capillarization and energy potential.

Animals↗
PubMed2002

[A system for biomaterial handling and sample pretreatment in conditions of weightlessness].

To perform laboratory biochemical, immunologic and microbiological analyses and special pretreatment and stabilization of biosamples immediately on the space station, system Plasma-03 was designed and manufactured and associated procedure for sample collection and pretreatment was developed. Main elements of the system are a refrigerator/thermostat, centrifuge and returnable container, and a set of accessories and expendables. The system meets the requirements to the equipment to be employed in crew health monitoring and biochemical experiments on board the International space station.

Biochemical Phenomena↗
PubMed2002

[Orthostatic tolerance after spaceflight or simulated weightlessness by head-down bed-rest].

Cardiovascular modifications, specially orthostatic intolerance (OI) are well known after spaceflight or long duration head-down bed-rest (HDBR) There is no agreement about their mechanisms. The aim of the study was to compare OI after a 42 day HDBR (n = 7) and after a 90 to 198 day spaceflight (n = 10). The studies were made during a stand test of 10 minutes for HDBR following 10 min in supine position and 5 min in sitting position. In both groups the variables measured were blood pressure (BP by transcutaneous plethysmography, Finapres) and ECG for RR interval (RRi) determination which allowed us to calculate autonomic indexes by spectral analysis of RRi and to determine spontaneous baroreflex sensitivity. In the cosmonaut group, 1 subject experienced a vaso-vagal syncope and 2 asked to stop the test without a decrease in BP. In HDBR, 4 subjects out of 7 did not perform the whole stand test (1 vaso-vagal syncope, 1 tachycardia and 2 hypotensions). Cosmonauts or HDBR subjects had common profiles: tachycardia and a decrease in parasympathetic index and baroreflex sensitivity. Both groups have an OI (30% of the subjects). However the mechanisms are different even if they have a common postural orthostatic tachycardia syndrome (POTS). The spaceflight duration was not determinant and we have no indice to predict OI which was one of the aims of the study.

Adult↗
PubMed2002

[Effects of dietary n-3 polyunsaturated fatty acid on lipid metabolism in rats under simulated weightlessness].

Objective. To study the effect of dietary n-3 polyunsaturated fatty acid (PUFA) on the lipid metabolism of tail-suspended rats. Method. 49 male Sprague-Dawley rats were divided into five groups: tail-suspension group I, fed with 10 wt % corn oil, tail-suspension groups II, III, IV were fed with three levels of fish oil (0.5, 1.5 or 3.0 wt %; low, middle and high level of fish oil, respectively). Group V fed with 10 wt % corn oil served as normal control. Result. Viscoelasticity of cell membrane in group III was significantly higher than that of group I (P<0.01); Vascular endothelial cells (VEC) was less in group II compared to group I; Serum total cholesterol (TC) and triglyceride (TG) , serum lipoprotein were lower in groups II, III, IV compared to group I, the higher fish oil content in diet, the lower serum lipid concentration in microgravity. Conclusion. Dietary n-3 PUFA do have distinguished effect on lipid metabolism and n-3 PUFA have certain effects on prevention of atherosclerotic disease and coronary heart disease in rats.

Animals↗
PubMed1972

Energy requirements of man living in a weightless environment.

The ability to maintain energy balance is a vital factor in maintaining body composition. A negative energy balance requires that body tissue be consumed to sustain biochemical and physiological activity. Such a caloric imbalance coupled with reduced physical activity results in (among other things): a negative balance which can not be reversed by increased protein intake; negative balances for electrolytes; and a suspension of erythrocyte production. Body weight losses were experienced by all astronauts during Gemini and Apollo missions. Data on the magnitude of the changes, together with data on energy consumption, were used to calculate energy imbalances. These data, when compared with results obtained from precise energy balance measurements made on 64 men living in low pressure chambers, show close correlation. When energy requirements are expressed in kilocalories per kilogram of body weight, the difference in energy requirements among the astronauts and chamber subjects was small and not statistically significant. These data indicated that reliable prediction of energy needs for astronauts, during long-term space missions, can be made by studying either the astronauts or healthy subjects in a ground-based environment similar to that of the spacecraft. These data also indicate that changes in body weight and certain other body measurements detected during Gemini and Apollo missions were probably caused, at least in part, by a calorie deficit.

Adipose Tissue↗
PubMed1976

Characteristics of postural self-regulation in complex spatial environments and after-effects of weightlessness.

The structure of the postural-spatial activity of parachuters, high-board divers and volunteers has been studied during postural tests on sports towers and that of cosmonauts before and after space flight. The experimental results give evidence that the stabilographic pattern shows several different types which correspond to the fixed, "searching" and pliable models of postural self-regulation, regardless of professional experience. During postural tests the cosmonauts exhibited deformation of the stabilographic pattern which lost its individual features and was converted into a stable curve which was represented by unmodulated fluctuations with a period of 0.15 sec that was similar to the fixed model. Psycho-physiological mechanisms of the changes are discussed.

Adaptation, Physiological↗
PubMedDate not supplied

[Pattern of spontaneous oculomotor activity in weightlessness and the readaptation period].

The results of one part Spontaneous Oculomotor Activity Study of Soviet-Bulgarian experiment "Labyrinth" conducted with the participation of 5 cosmonauts prior to and after 10- and 241-day flight are presented. Two cosmonauts have also been studied in-flight. The experiment was conducted with the use of automated data controlling and processing system "Zora" developed by the Bulgarian specialists on a personal computer basis. The horizontal and vertical electrooculograms were recorded in the subjects with eyes closed, open and open but shaded by opaque glasses with the gaze directed forward and in extreme left, right, up and down directions of the gaze. It is found that in the first 3 day of space flight especially when locking visual input, there is an increase in spontaneous activity of "swimming" and saccadic nature or spontaneous nystagmus mainly in the vertical direction. There have been sharp decreases in the rate of eye movement and increase of an amplitude when placing the eyes in the extreme positions (especially in up-down directions) accompanied by correcting saccades or adaptive nystagmus. The post- and inflight changes in the severity and pattern of spontaneous oculomotor responses were similar.

Adaptation, Ocular↗