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At least 631 records · Page 35Linked to original sources
PubMed1998

Cellular adhesion in neoplastic and syngeneic normal cells under altered gravitational conditions.

The major objective of several experiments performed in space in the last 15 years was to establish whether single cells are sensitive to gravity. It was found in certain cells that reduced gravity leads to profound changes of a number of physiological functions like genetic expression, cell proliferation, signal transduction and cytoskeleton structure. In cell biology studies microgravity can be simulated on Earth in the clinostat. Nearly all data on experiments in the clinostat are related to cells cultured in suspension and, therefore, to adhesion-independent cells. In contrast, several biological phenomena as neoplastic transformation, cell differentiation, in-vitro cellular aging, contact inhibition and cellular adhesion require mainly cellular systems that are adhesion-dependent. The purpose of this work was: a) to study the behaviour of two rat cell strains (neoplastic SGS/4A and syngeneic fibroblasts FG) in order to test whether adhesion-dependent cells are suitable for clinorotation and b) to investigate cell-cell and cell-substratum adhesion in these cells kept under simulated low-g in the fast rotating clinostat and in hypergravity at l0g in the centrifuge.

Animals↗
PubMed1975

[Effect of gravitational loads of a training nature on the blood vessels of the rabbit spinal cord].

Three series of experiments were performed in 47 rabbits. The cerebral vessels were studied by methods of injection and clearing. In the first series under study were vessels after exposure to stresses of a training type. The picture of the circulatory bed under these conditions was close to normal in morphological parameters (diameter of vessels, amount of visible vessels, distinctness, evenness of the contours pronouncement of networks etc). In the 2nd and 3d series the results of training were checked by a single exposure to a series of stresses or a solitary stress. The data obtained suggest increased resistance in majority of trained animals to the following hypergravitation and better morphological parameters of the spinal cord circulatory bed as compared with not trained animals. Hence, certain adaptation to the following hypergravitation can be obtained in rabbits by means of repeated rotations in a centrifuge according to a special schedule of training.

Adaptation, Physiological↗
PubMed1975

The influence of variable gravitational fields on the embryonic development of some ecaudate amphibians.

The fertilized eggs of the frog Rana temporaria immediately after fertilization were rotated on a clinostat in the vertical plane at the rate of 0.66 rotations per minute with a radius of 20 mm for 2.5 hours. A wide spectrum of developmental anomalies was found (33% in the experiment, 14% in the control) which, in the authors' opinion, result from abnormalities in the cortical reaction of symmetrization. These abnormalities manifest themselves in the irregular distribution of cortical pigment and in eccentric division lines.

Animals↗
PubMed1966

Physiological effects of gravitation.

The physiological effects of weightlessness are discussed, as they were measured and reported by the Russian cosmonauts. The possibilities of adaptation to space environment by training and the mechanisms of compensation and vicarization (adaptive substitution) of the analyzers and processes of the biological entity are considered. The authors present recommendations for cosmonaut training for distant and prolonged flights.

Acceleration↗