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Biomedical subjects

A Billitteri

Publications and source records attributed to A Billitteri.

At least 19 recordsLinked to original sources
PubMed1992

[Action of retinol on viable cell recovery and clonogenic potential of HTC cells after in vitro hyperthermia].

The aim of this study was to investigate if the association of both hyperthermic and Retinol treatment of HTC hepatoma cells could be useful in antitumor therapy. Treatment with 5 microM Retinol was carried out before or after hyperthermia (42 degrees C or 44 degrees C, one hour; in the latter case it was performed in cells already thermo-selected. We took into consideration two parameters, i.e. the number of the collected vital cells (evaluated by the trypan blue-exclusion test) and the clonal efficiency of these cells (calculated as number of colonies obtained from 250 cells cultured for 5 days). Thermal treatment alone caused a decrease of the number of the collected vital cells and of their clonal efficiency only in the cell cultures incubated at 44 degrees C. Instead the control thermo-selected cells, both at 42 degrees C and at 44 degrees C, showed both decreased clonal efficiency and yield of the vital cells. Compared with the control cultures treated with 0.1% Ethanol, used as vitamin A solvent, only cell cultures treated with Retinol before hyperthermia showed a decreased number of collected viable cells, nevertheless their clonal efficiency was unchanged.

Animals↗
PubMed1992

[Effect of hyperthermia and retinol treatment in vitro on HTC cell adhesiveness to laminin and fibronectin].

Since cell adhesiveness is very important in the metastatic process and because both hyperthermia and treatment with Retinol can modify the fluidity of the lipid components of the plasma membrane (and therefore its receptor distribution), we investigated if a hyperthermic treatment (at 42 degrees C or 44 degrees C, for one hour) of HTC hepatoma cells, preceded or followed by treatment with 5 microM Retinol, could alter cell adhesiveness to Laminin or to Fibronectin-coated substrata. Hepatoma cells, after such treatments, were collected and processed by Auerbach's method. In the control cells thermal treatment alone caused a decrease of adhesiveness to Laminin but no change in that to Fibronectin. When treatment with Retinol was carried out before hyperthermia, the cells showed an increased adhesiveness to Laminin and a decreased adhesiveness to Fibronectin. Instead, when treatment with Retinol was performed in cells previously thermo-selected, a decrease of adhesiveness to both tested ligands was observed.

Animals↗
PubMed1989

[Actions of retinol and retinoic acid on hepatoma H4 cultures].

The amount of vital cells recovered, their morphology (studied by SEM) and some of their biochemical aspects concerning the differentiation processes (aerobic glycolysis, cell production of cAMP and CEA) were investigated in a strain of H4 hepatoma cultured for 8 days in the presence of 5 microM retinol (R) or retinoic Acid (RA). Vital cell recovery is slightly reduced either by R or RA treatment. Flattening of the cell shape and reduction of the plasma membrane prolongations and of intercellular bonds are observed in the R-treated cells but to a greater extent in those treated with RA. Aerobic glycolysis is decreased in the R-treated cells but increased in those treated with RA. Such events could be related to the regressive processes observed in the RA-treated cells. cAMP cell content is increased to a greater extent in the R-treated cells than in those treated with RA. CEA cell content is greatly decreased in the RA-treated cells but only slightly in those treated with R. Therefore, the treatment of HA hepatoma cells with 5 microM R or RA, while reducing cell growth only slightly, does not cause evident and unequivocal morphological and biochemical events related to cell redifferentiation.

Animals↗
PubMed1983

Effect of lipophilic vitamins on the erythrocyte membrane. 31P NMR and fluorescence studies.

Structural changes induced by the fat-soluble vitamins A, D3, E and K1 in natural membranes were studied by 31P NMR and fluorescence anisotropy on erythrocyte ghosts; the occurrence of cell fusion following vitamin addition was detected by optical microscopy of intact cells. Vitamins A, E and K1, which produce cell fusion, also induce the formation of configurational phases other than the bilayer and increase, at a different extent for the different vitamins, membrane fluidity. Vitamin D3, on the contrary, induces aggregation without fusion, paralleled by bilayer phase stabilization and microviscosity increase. A correlation between fusion phenomena and structural variations in the bilayer organization is therefore suggested.

Animals↗
PubMed1982

[Biochemical and ultrastructural research on the antagonism between vitamins A and D at the leve of the erythrocyte membrane].

The reason for the antagonistic action between retinol and cholecalciferol on cellular membranes was investigated "in vitro" on human erythrocytes, by testing their lipoperoxide production, the amount of membrane-bound retinol and the morphology of these cells by scanning electron microscope. Lipoperoxides were assayed by TBA-test; the membrane-bound retinol was tested by the Karr-Price method on lipids extracted from red blood cells by the Folch method and vitamin D-deprived by TCL chromatography; the morphological changes of these cells treated with vitamin A, or D, or A+D, were tested by scanning electron microscope. In our experimental system both retinol and cholecalciferol increase the lipoperoxide production from the erythrocytes; nevertheless no synergism of action can be demonstrated between the two vitamins. Cholecalciferol decreases the amount of membrane-bo und retinol as well as the changes produced by vitamin A in red blood cell surface. These results are in good agreement with our previous observations obtained by nuclear magnetic resonance, using the same experimental system.

Binding, Competitive↗
PubMed1980

[Role of erythrocyte membrane lipids in the antagonism between vitamin A and D3].

The "in vitro" lytic effect of retinol (35 microM) on various animal species erythrocytes is partially inhibited by cholecalcipherol. The inhibition observed is not related with reduction of retinol bound by erythrocytes membranes while it can be related with the amount of glycolipids not gangliosides of these cells. Instead, we have observed that the amount of retinol molecules bound to erythrocytes membranes and their haemolysis can be related with the gangliosides contents of red cells membranes.

Animals↗
PubMed1978

[Action of vitamin D and E on the erythrocyte membrane. II. Morphological changes in the erythrocytes studied by transmission electron microscopy].

Man, rabbit, guinea-pig erythrocytes treated "in vitro" with high doses of cholecalcipherol or alpha-tocopherol release K+ and haemoglobin and show ultrastructural damages. These damages consist in a change of the red cells profile as well as in the desappearance of the glycocalix, in alterations of the membrane and of the cortical cytoplasm structure. These ultrastructural alterations are of a different degree, depending on the animal species; they partly resemble the erythrocyte changes induced by retinol. Our results are in partial agreement with the Dingle and Lucy's hypothesis on the common action of liposoluble vitamines on the erythrocyte membrane.

Animals↗
PubMed1978

[Effect of vitamin D and vitamin E on the erythrocyte membrane. I. Effect on in vitro osmolar resistance and lysis].

As in the case of retinol, low doses of cholecalcipherol and alpha-tocopherol "in vitro" increase the osmotic resistance of red blood cells, while high doses have a lytic effect on the erythrocytes of various animal species (e.g.: man, sheep, rabbit, guinea-pig, mouse, rat) with the exception of the chicken. The haemolytic effect of cholecalcipherol is less intense than that of retinol; alpha-tochopherol, while causing even less haemolysis than cholecalcipherol, involves a remarkable loss of K+ from the red cells. Besides these quantitative differences, the mechanism of action of the three vitamins seems somewhat different, as shown by modifications of the suspension medium (e.g.: pH, temperature, presence of proteins and reducing substances) or by treatment of the red cells with trypsin. Our results therefore essentially confirm the hypothesis of Dingle and Lucy of common mechanism of action of liposoluble vitamins on biological membranes.

Cholecalciferol↗