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Biomedical subjects

F Fabia

Publications and source records attributed to F Fabia.

17 recordsLinked to original sources
PubMed1981

In vivo ageing of human erythrocytes and cell-surface labeling by D-galactose oxidase and sodium borotritide.

Young and old, human erythrocytes, separated in vitro according to their age in vivo, were radioactively labeled at the cell-surface D-galactosyl and 2-acetamido-2-deoxy-D-galactosyl residues by treatment with D-galactose oxidase, followed by reduction with sodium borotritide. The labeling was quantitatively determined for each type of erythrocyte by measuring the molar amounts of borohydride necessary for the complete reduction of the oxidized residues. The number of surface residues per blood-group A+ erythrocyte was found to be 37.6 +/- 1.8 x 10(6) (n = 8) for young, 21.8 +/- 4.9 x 10(6) (n = 8) for old, and 24.8 +/- 6.4 x 10(6) (n = 8) for middle-aged erythrocytes, indicating a significant decrease of the residues during ageing.

ABO Blood-Group System↗
PubMed1981

Decrease of carbohydrate in membrane glycoproteins during human erythrocyte ageing in vivo.

Membrane glycoproteins from young human erythrocytes and erythrocytes aged in vivo were fractionated by gel filtration. Three major groups of glycoproteins were obtained. The neutral hexoses and sialic acid contents of each group of glycoproteins from the old cells were found to be significantly reduced by comparison to the values found in the glycoproteins of the young cells. Thus, the previously observed decrease in neutral hexoses and in sialic acid contents of the full erythrocyte membrane during in vivo ageing does not affect only one particular group of glycoproteins but each of the groups of glycoproteins tested, including the major glycoproteins of the erythrocyte membrane, that is to say glycophorins. It is shown in addition, that the previously observed decrease per cell of the surface galactose and N-acetylgalactosamine residues of the ageing erythrocyte affect several groups of membrane glycoproteins including band 3, PAS-1, PAS-4 and PAS-3. The physiological significance of these experimental data is discussed.

Chromatography, Gel↗
PubMed1980

Individual variations of the seven carbohydrate components of human erythrocyte membrane during aging in vivo.

The contents of fucose, mannose, galactose, glucose, 2-acetamido-2-deoxy-D-glucose and -D-galactose, and sialic acid, when the results were expressed as nmol per mg of membrane dry-weights, were found to be significantly lower in the membranes of old erythrocytes than in the membranes of young ones. No significant difference was found between young and old membranes when the compositions were expressed as residues per one hundred carbohydrate residues, suggesting that a homogeneous decrease of the carbohydrate moieties may occur during aging in vivo.

Erythrocyte Aging↗
PubMed1979

Physiological ageing of red blood cells and changes in membrane carbohydrates.

Evidence is presented to indicate a generalized role for the terminal sialic acid residues of circulating erythrocytes. After reinjection into their donors, neuraminidase-treated human, rabbit, rat and dog erythrocytes were promptly removed from the circulation : intect erythrocytes, previously incubated under the same conditions but without neuraminidase, were removed after a significantly longer period. The neuraminidase-treated erythrocytes were cleared by the liver and in a little part by the spleen. Old and young human, rabbit, rat erythrocytes contained different quantities of stromal sialic acid, significantly lowered on the old cells. But the half-life of old intact rabbit erythrocytes is sigificantly shorter than that of neuraminidase-treated young erythrocytes with a similar minidase-treated young erythrocytes with a similar sialic acid content. Indeed sialic acid is not the only carbohydrate component of the membrane that is decreased during erythrocyte ageing, the others membranous sugars are decreased too. Theses changes in the carbohydrate moity could have a role in the clearance of the erythrocytes.

Animals↗
PubMed1978

Effects of ageing, surface sialic acid and glycopeptides of erythrocytes on auto-rosettes in man.

Human red blood cells can bind in vitro to autologous peripheral blood lymphocytes forming auto-rosettes. The percentage of rosett-forming cells (A-RFC) depends on erythrocyte ageing in vivo. Old untreated cells given an A-RFC percentage lower as compared with the young ones. The same age groups of cells treated with neuraminidase show a parallel increase of A-RFC as compared with untreated cells. No significant difference is found between young and old cells with high concentrations of neuraminidase. The rosetting formation is inhibited by the pre-treatment of lymphocytes with erythrocyte glycopeptides released by trypsin. This suggests that auto-rosetting is mediated by erythrocyte surface glycopeptides in which sialic acid plays a role directly or not.

ABO Blood-Group System↗
PubMed1977

Carbohydrate content of human red cell membrane in patients with cirrhosis of the liver.

The protein and carbohydrate contents of red cell membranes from 12 patients with liver cirrhosis were compared to those from 12 normal donors. Protein content was significantly higher and surface sialic acid and neutral hexoses were similar, whereas surface fucose and hexosamine were significantly lower in the cirrhotic red cells. The role of these membrane modifications is discussed.

Blood Proteins↗
PubMed1975

[Immunologic changes and infections in alcoholic cirrhosis].

The authors explored humoral and cellular immunity in 50 cases of alcoholic cirrhosis. The levels of the three serum immunoglobulins were greater than normal. IgM was significantly higher. The levels of antipolio antibodies (types I, II and III) were significantly higher in cirrhosis than in controls. The antistreptolysin and antistaphylolysin titers showed that the differences between levels found in cirrhosis and in controls were not significant. After taking the Sabin polio vaccine, variations in antipolio antibodies remained within normal limits, considering the high levels noted before taking the vaccine. Total serum complement was normal in 90% of the estimtions carried out. The results of the intradermal reactions were dissociated. Tuberculin skin tests were negative in 35% of cases of cirrhosis and in 14.3% of controls. In skin tests for candida and streptococcal antigen, differences between cirrhotics and controls were not significant. The absolute figure for blood lymphocytes per mm-3 was, in half the cases, less than normal.

Alcoholism↗
PubMedDate not supplied

[Plasmodium chabaudi: changes in the surface sialic acids of red blood cells during infection (author's transl)].

Surface sialic acids of mice red blood cells infected with the malarial parasite Plasmodium chabaudi are increased as compared to extracts of red cells from normal mice. This increase occurs coincidentally when reticulocytes increase in the peripheral blood. The same increase of surface sialic acids is shown by studies of reticulocytes from phenylhydrazine treated mice. Similarly, neutral hexoses, fucose, were found in greater quantities in surface glycopeptides obtained after incubation with trypsin of reticulocytes from phenylhydrazine treated mice than in surface glycopeptides of red cells from normal mice. This increase occurs also in Plasmodium chabaudi infected red cells with the development of reticulocytosis, in the same way. These facts suggest the contribution of reticulocytes to the biochemical changes observed during malaria infection.

Animals↗