Search PubMed⌕ Search

Biomedical subjects

A Cogoli

Publications and source records attributed to A Cogoli.

At least 19 recordsLinked to original sources
PubMed1992

Effect of head-down tilt bedrest (10 days) on lymphocyte reactivity.

Immunological responses of six healthy males to 10 days of head-down tilt bedrest (HDT) were assessed. Lymphocyte responsiveness was severely reduced immediately before, during, and immediately after the HDT, even though the lymphocyte numbers did not change. By contrast, delayed-type hypersensitivity was not affected. No dramatic changes were found in WBC counts and lymphocyte subpopulations, with the only exception of natural killer (NK) cells which transiently decreased immediately after HDT. Plasma cortisol levels were elevated above normal immediately before and during the HDT. The data suggest that the mitogenic response of lymphocytes was affected by psychological and fluid shift stress. These results are compared with data obtained during and after spaceflight. We conclude that the stress of HDT induces changes in immunological responsiveness that are strikingly similar to those arising from the stress of spaceflight.

Adult↗
PubMed1990

A ground-based model to study the effects of weightlessness on lymphocytes.

The mitogenic response of human lymphocytes was found to be markedly reduced in weightlessness conditions as compared to normal gravity. One possible explanation is that due to the non-existent sedimentation in space the lymphocytes could not adhere and spread on a substratum. Thus, we investigated the effect of substratum adhesiveness on lymphocyte responsiveness by reducing and blocking cell adhesion with poly-HEMA in a simple on-ground system. Lymphocyte adhesiveness was assessed by measuring the proportion of non-adhesive, slightly, and strongly adhesive 51Cr-radiolabelled cells on uncoated and poly-HEMA coated plastic. The amount of cell spreading on surfaces with varying adhesiveness was determined by measuring the area of cells. Cells grown on medium and thick poly-HEMA films were rounded in shape. By contrast, on tissue culture plastic, they showed clear signs of spreading. The mitogenic response of lymphocytes grown on thick poly-HEMA films was reduced by up to 68% of the control (tissue culture plastic). Interferon-gamma production was virtually nil when the cells were grown on the least adhesive substratum. These results show that activated lymphocytes need to anchor and spread prior to achieving an optimal proliferation response. We conclude that decreased lymphocyte adhesion could contribute to the depressed in vitro lymphocyte responsiveness found in the microgravity conditions of space flight.

Cell Adhesion↗
PubMed1990

Effect of a herbal yeast food supplement and long-distance running on immunological parameters.

The effect of a food supplement on immunological parameters of 16 long-distance runners was tested in a randomized, double-blind and placebo-controlled trial. The supplement comprised plasmolysed herbal yeast, malt, honey, and orange juice. No statistically significant differences between the two groups regarding the following variables were detected at three sessions at rest and immediately after a 21 km run: total and differential white blood cell counts, numbers of B- and T-cells and T-subpopulations, concanavalin-A-induced lymphocyte proliferation, serum levels of immunoglobulins, neopterin, IL-2 receptors, beta 2-microglobulin, complement factor b, c4 and c3c, and c1-inactivator. These findings suggest that the effects of the tested food supplement on these parameters are negligible with respect to improvements in the immunological status of long-distance runners. The changes observed immediately after the run had a transient character. In both groups, however, low lymphocyte counts, IgG subclass 2 levels and c1-inactivator levels were noted at rest, which indicate that the immune status of endurance athletes may be affected by training.

Adult↗
PubMed1990

[Effect of dimethyladipimidate and dimethylsuberimidate on cell-cell adhesion in rat fibroblasts].

In a study performed to identify the molecular mechanisms which regulate cell to cell adhesion and contact inhibition in neoplastic and syngeneic normal cells of the rat we have observed that the adhesive capacity depends on the reagents used, either EDTA or trypsin, to release the cells from monolayer. Taking profit of this last property and of the possibility of blocking free -NH2 groups on membrane proteins with specific cross-linking reagents "in vitro", we have studied in this work the behaviour of the proteins of the cell coat involved in cell to cell adhesion of rat fibroblasts FG/2. The cross-linking reagents used were dimethyladipimidate (DMA) and dimethylsuberimidate (DMS). The cells were exposed to the reagents at 0 degrees C for 30'. Cell to cell adhesion was measured by determining the percentage of single cells labeled with 3H-leucine, adhering to a confluent monolayer at different incubation times. The inhibitory effect on cell to cell adhesion brought about by cross-linking reagents indicates that a) EDTA-released cells are more sensitive to both imides than those released with trypsin, b) DMA is more effective on trypsin-released cells and c) DMS is more effective on EDTA-released cells. Therefore, we conclude that the inhibition of adhesion by reaction with the two cross-linking reagents is more likely due to a stiffening of the molecules of the cell coat involved in the adhesion, rather than to the modification of -NH2 residues which should specifically participate to adhesive process.

Animals↗
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↗
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↗
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↗
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↗