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Biomedical subjects

A Cogoli

Publications and source records attributed to A Cogoli.

At least 73 records · Page 4Linked to original sources
PubMed1988

Gravitational effects on mammalian cells.

In this paper we present first the results of our most recent investigations on gravitational effects on the activation of human lymphocytes: by immunoenzymatic staining and by using concanavalin A (Con A) coated to red blood cells (RBC) we demonstrate that the increase of activation measured at 10xg is due to a simultaneous activation of T- and B-lymphocytes whereas at 1xg only T-cells are stimulated. Conversely, activation of T-cells by chemical modification of the membrane with sodium periodate is depressed at 10xg. Secondly, experiments performed in the centrifuge as well as in the clinostat with Friend, K-562, and hybridoma cells show that each cell line develops its own adaptation reaction to gravitational stress.

B-Lymphocytes↗
PubMed1988

Effect of long-term physical exercise on lymphocyte reactivity: similarity to spaceflight reactions.

The response of critical immunological parameters in seven athletes to the sustained physical stress of marathon running was assessed. Variables analysed were the responsiveness of lymphocytes (measured as mitogenic response to concanavalin A), the numbers of lymphocytes, their subsets, and leukocyte numbers. In addition, blood levels of cortisol, epinephrine, and norepinephrine were determined. After the run, lymphocyte responsiveness was severely depressed to 1-70% of the resting values, even though the lymphocyte counts did not change. Leukocyte counts were elevated 2.8-fold. No dramatic changes were found within the lymphocyte subsets, although an increase in pan T-cells and the helper/inducer subset 2 d after the run was significant. In addition, the numbers of B-cells decreased significantly. No change was observed within the suppressor/cytotoxic subset. Cortisol increased 2.1-fold, epinephrine 3.2-fold and norepinephrine 2.7-fold. All these parameters returned to baseline values within 2 d. These data were compared with data obtained during and after spaceflight. We conclude that prolonged physical stress of marathon running induces changes in immunological responsiveness that are strikingly similar to those arising from the stress of spaceflight.

Epinephrine↗
PubMed1986

Effects of hypergravity on "whole-blood" cultures of human lymphocytes.

The purpose of this paper is to present a detailed description of the effects of hypergravity on the mitogenic response of human lymphocytes to concanavalin A. The effect on cultures of lymphocytes isolated from peripheral blood are compared with those on whole-blood cultures obtained by diluting fresh blood with culture medium 1:10. Whole-blood cultures of lymphocytes from crew members will be investigated inflight on the Spacelab missions D-1 in 1985 and SLS-1 in 1987. In hypergravity there is an increase in lymphocyte activation of up to 500%. A similar increase can be induced by pre-incubating the cultures in hypergravity prior to exposure to concanavalin A at 1 G. The effect is less evident in cultures of isolated lymphocytes. The influence of autologous plasma and erythrocytes has also been investigated. Plasma and hypergravity have a synergistic and positive effect on lymphocyte activation, i.e. cultures of separated lymphocytes show the highest activation when incubated at 10 G and supplemented with autologous plasma. Conversely, erythrocytes depress lymphocyte activation.

Adaptation, Physiological↗
PubMed1985

Lymphocyte reactivity during spaceflight.

Over twenty years of spaceflight have demonstrated that man can easily survive and work in weightless conditions. However, a number of physiological changes may affect crew performance in space. Besides the well known disturbances of the vestibular and cardiovascular systems, bone demineralization, and decrease of erthrocyte mass, certain immunological alterations have been observed in space crews after flight. One of them--the reduction of lymphocyte reactivity to mitogens--was the subject of our investigations during the flight of Spacelab 1 from 28 November - 8 December 1983.

Cells, Cultured↗
PubMed1984

Cell sensitivity to gravity.

Cultures of human lymphocytes exposed in microgravity to the mitogen concanavalin A showed less than 3 percent of the activation of ground controls. This result supports the hypothesis, based on simulations at low g and experiments at high g, that microgravity depresses whereas high gravity enhances cell proliferation rates. The effects of gravity are particularly strong in cells undergoing differentiation.

Cell Differentiation↗
PubMed1984

Bioprocessing in space: human cells attach to beads in microgravity.

Attachment to a substrate and survival of human embryonic kidney (HEK) cells have been tested in an incubator installed in the flight-deck of the Space Shuttle 'Challenger' during its eighth mission. HEK cells are producing the enzyme urokinase and are presently investigated as candidates for electrophoretic separation in an apparatus developed and manufactured by McDonnell Douglas. Attachment of HEK cells to a substrate is mandatory for survival and production of urokinase after electrophoretic separation. Analysis of the samples shows that cells adhere, spread and survive in microgravity (< 10(-3) x g) conditions as well as the ground controls at 1 x g. This result represents an important step towards further bioprocessing in space.

Biotechnology↗
PubMed1983

Hypergravity promotes cell proliferation.

When HeLa cells, chicken embryo fibroblasts, sarcoma Galliera cells, Friend leukemia virus transformed cells and human lymphocytes are cultured in a hypergravitational field (e.g. 10 X g) proliferation rate is increased by 20-30%, whereas glucose consumption per cell is lower than at 1 X g. Tracking of cell movements on gold-coated substrates reveals that cell migration is hindered at high-g. These findings suggest that under gravitational stress the cell is either capable of shifting to other metabolic pathways and/or consumes less energy at high-g than at 1 X g. This work describes ground-based investigations related to experiments to be performed on future Spacelab missions.

Animals↗
PubMed1983

[Electron microscopic features of neoplastic cells (SGS-3A) cultivated in agar].

The agar suspension culture method was applied to enrich for neoplastic cells in cultures of a cellular strain (SGS-3) derived from Sarcoma Galliera. This method suppresses the growth of normal cells without impairing colony formation by neoplastic cells. The analysis by electron microscopy of colonies of SGS-3A cells cultured in agar medium shows that cytoplasmatic bridges are present in the regions of cell-cell contact.

Agar↗
PubMed1982

Cell morphological, ontogenic, and genetic reactions to 0-g simulation and hyper-g.

Organisms use gravity for spatial orientation, and differentiation into species during evolution follows geological processes which are caused by gravity. On the other hand, the task of most organismic functions which have or may have a relation to gravity is to compensate gravity. Furthermore, today it is very obvious that organisms do not disintegrate under the conditions of weightlessness, at least for the currently tested durations. These previous statements indicate a large field of still unknown regulation and adaptation mechanisms. Experiments to simulate weightlessness on the fast clinostat and with hyper-g show a highly developed ability of the genetic chain and of differentiating cells in being autonomous against mechanical stresses caused by outer accelerations. Nevertheless, different strong and slight changes of different tested end points were found. The question remains if the cells react actively or only passively.

Animals↗
PubMed1981

[Preliminary reports on homologous and heterologous intercellular adhesion in normal and neoplastic cells cultured in vitro].

In our researches on the molecular meccanisms of cellular adhesion and density dependence inhibition we observed the SGS-3A neoplastic cells show a cell-cell adhesion higher than the homogenetic fibroblasts. This adhesion increases in single cells prepared with EDTA rather than Trypsin. Specific and non specific intercellular adhesion assays demonstrate that ligand molecules of coat of neoplastic cells are strongly trypsin-sensitive; on the contrary ligand molecules of coat of fibroblasts are more trypsin-resistent.

Animals↗
PubMed1981

Determination of adhesive rate constant in normal and neoplastic homogeneic cells.

The adhesive rate constant (ARC) of neoplastic SGS-2 cells which have a low contact inhibition, is remarkably higher than that of normal homogeneic fibroblasts. This is in contrast with the mutual adhesion theory which states that the loss of contact inhibition is strictly related to the loss of cell recognition and consequently to the loss of cell adhesion capacity.

Animals↗
PubMed1981

[Effect of iodoacetamide on cell-cell adhesion of fibroblasts in the rat].

The -SH groups of rat fibroblasts of cell-coat were blocked with Iodacetamide. This substance interferes negatively on the homologous intercellular adhesion of the tested cells, with a proportional effect related to the concentration used. The meaning of -SH groups on the cell-cell interactions is discussed.

Animals↗