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Biomedical subjects

P Cornillot

Publications and source records attributed to P Cornillot.

At least 19 recordsLinked to original sources
PubMed1983

in vivo Ageing of human erythrocytes and cell-surface labeling by metaperiodate and sodium borotritide.

Young and old human erythrocytes, separated in vitro according to age, were labeled at the surface-sialic acid residues by sodium periodate and borotritide treatment. No qualitative difference was observed between the sialic acid derivatives of young- and old-erythrocyte membranes. The number of labeled residues was significantly decreased in the in vivo aged erythrocytes (12 +/- 2.8 X 10(6); n = 8) when compared to the young ones (19.4 +/- 2.8 X 10(6); n = 8). Analysis of the labeled glycoproteins by sodium dodecyl sulfate gel-electrophoresis showed that this decrease affects the PAS-1, PAS-4, PAS-2, and PAS-3 bands (glycophorins A and B) of the old-erythrocyte membranes.

ABO Blood-Group System↗
PubMed1983

Red cell ageing: phagocytosis and life-span of young and old erythrocytes fractionated by centrifugation.

Young and old red blood cells, separated by centrifugation on the basis of differences in cell density, were submitted to phagocytosis by either autologous human alveolar macrophages or syngeneic murine bone-marrow macrophages. Young cells adhere to macrophages, but to a much smaller extent than old ones. The influence of both type and quality of the separation procedure on the differences observed between the two erythrocyte subpopulations is discussed in the light of the half-life times of murine young and old red blood cells. Fractionation according to age was obtained following the method of Murphy (1973) and glutamate oxalo-acetate transaminase activity was measured and used as an indicator of both cell age and separation.

Animals↗
PubMed1982

Design and feasibility of a flexible computerized system for the clinical laboratory, based on the IEEE 488 standardized interface.

Our target is to build a flexible computerized system based on an informational study of the clinical laboratory, which would leave the laboratory staff free to use equipment or modules from different manufacturers interchangeably. This applies to hardware and software. To fulfil this objective, it is necessary that automatic analyzers, microcomputers and minicomputers, have built-in standardized hardware and software interfaces. Technical specifications of the IEEE 488 standardized interface, recommended by the authors, are presented here; this interface is already widely used in instrument interfacing with low-cost microcomputers are minicomputers but has not yet been used for clinical laboratory automatic analyzers. A design for a flexible laboratory based on this interface is presented, with a discussion of the feasibility of such a project.

Autoanalysis↗
PubMed1982

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

1. Young and old rat 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-galactose (Gal and GalNAC) residues by treatment with D-galactose oxidase, followed by reduction with sodium borotritide: 2. The number of labeled surface residues per erythrocyte was found to be 0.52 X 10(6) +/- 0.08 X 10(6) for young, 0.38 X 10(6) +/- 0.05 X 10(6) for middle-aged and 0.32 X 10(6) +/- 0.05 X 10(6) for old, indicating a significant decrease of these surface Gal and GalNAC residues during ageing. 3. Qualitative changes were observed between the sodium dodecyl sulfate electrophoretic patterns of young, middle-aged and old labeled erythrocytes. 4. Quantitative changes were previously observed between the electrophoretic patterns of the labeled glycoproteins from young, middle-aged and old human labeled erythrocytes. 5. It is concluded that some of the changes occurring during in vivo ageing of rat and of human erythrocytes are different.

Animals↗
PubMed1982

Failure of in vivo and in vitro resialosylation of VCN-desialylated erythrocytes in mammalian and non-mammalian species: evidence from agglutination studies with peanut-agglutinin.

1. In distinction to mammalian erythrocytes, splitting of sialic acids of non-mammalian erythrocytes (chicken and newt) by Vibrio cholerae neuraminidase (VCN) does not lead to a dramatic decrease in their viability. 2. One of the possibilities to explain this discrepancy is the ability of chicken and newt desialosylated erythrocytes to repair the enzymatic injury. 3. To test this hypothesis we used the property of peanut agglutinin (PNA) to agglutinate desialosylated erythrocytes. 4. Desialosylated erythrocytes of all the species tested remain PNA-agglutinable throughout their whole life time in the blood stream. The absence of effect of VCN on chicken and newt erythrocytes is therefore not due to their resialosylation.

Animals↗
PubMed1982

A glucose-containing fraction extracted from the young erythrocyte membrane is capable of transferring glucose to hemoglobin in vitro.

Red blood cell (RBC) membranes are rich in a glycoconjugate that is extractable in chloroform/methanol solutions (2/1, v/v) and contains several hexoses, such as glucose. Old and young RBC are separated and their respective glycoconjugates are prepared. HbA0 is purified by column chromatography and incubated with solutions of this conjugate. After 24-h incubation, Hb is dialyzed and the amount of glycosylated Hb is measured by a method of column chromatography adapted from Trivelli. A very significant amount of HBAlc is formed when young RBC extracts are incubated: 3.6% of total Hb becomes HBAlc with the extracts, versus 3.2% with free glucose, and only 2.5% for controls. No increase in HbAlc is obtained when extracts of old RBC are incubated. Another difference between the action of the glycoconjugate and free glucose is that the former induces the increase of only the HBAlc fraction, whereas glucose induces the increase of all the minor Hb fractions. The evaluation of glucose contained in the conjugate before and after the glycosylation reaction demonstrates that it is due to an exchange of glucose units from the conjugate to Hb. The reaction is stereospecifically inhibited by p-nitrophenyl-beta-D-glucoside. The nature of the formed HbAlc is demonstrated by isoelectric focusing. A slight increase of HbAlc observed in the incubated controls may be due to an internal migration of some residues of glucose primitively bound to lysyl residues in an unstable form and also to some degree of denaturation during the incubation.

Erythrocyte Membrane↗
PubMed1982

[Study of the interaction between desialylated erythrocytes and Kupffer cells using perfusion of liver in situ].

Desialylated erythrocytes, when perfused in mice liver in situ, were shown to be sequestered. This sequestration was inhibited by dihydrocytochalasin B and a neoglycoprotein: N-Acetylgalactosaminyl-albumin. Our results confirm that, under physiological conditions, the recognition of desialylated erythrocytes appear to be related to the presence of N-Acetylgalactosamine or galactose receptor on the surface of Küpffer cells.

Animals↗
PubMed1982

Receptors for peanut agglutinin in lymphocytes from patients with cirrhosis of the liver.

A population of peripheral blood lymphocytes exhibits specific receptor for the peanut lectin (Arachis hypogaea). In control subjects, this population represents 1.3% of all lymphocytes while it represents 13% in patients with alcoholic cirrhosis. The percentage of lymphocytes expressing this receptor appears to be correlated with hypoalbuminemia and the erythrocyte sedimentation rate, in these patients. Furthermore, a higher percentage of peanut positive lymphocytes was found in cirrhotic patients who subsequently died than in those who survived.

Adult↗
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↗
PubMed1981

[Interest of the determination of reference values for the monosaccharide composition of the human erythrocyte membrane (author's transl)].

The carbohydrate composition of the human erythrocyte membrane was just established ten years ago. Carbohydrates have crucial functions in the membrane structures and the determination of this composition may have an important semeiological signification. In this way, reference values are necessary. The existence of possible variations of the composition with two physiological parameters: the groups in the ABO system and the age of erythrocytes have been investigated and are reported. Their repercussion on the determination of reference values is discussed.

Blood Group Antigens↗
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↗
PubMed1980

The role of T-agglutinin in the disappearance of erythrocytes artificially aged by desialylation.

The chance discovery of two mouse strains, one with and one without a high presence of serum T-agglutinin, permitted the investigation of the role of this antibody in the disappearance of desialylated erythrocytes, which may be regarded as a model for ageing. The proportional relationship between the quantity of sialic acid removed and the diminution of half-life is not affected by the presence or absence of T-agglutinin. Opsonization by T-agglutinin would therefore appear to be an improbable mechanism. Other possible theories are discussed.

Agglutinins↗
PubMed1979

Carbohydrate content of human erythrocyte membrane. Variations with ABO-blood group.

The study of the carbohydrates of human erythrocyte membranes has been mainly focused on their glycopeptidic and glycolipidic complexes. Modifications of these carbohydrates have been described in subjects with various pathological states. In order to characterize possible changes of the glycopeptides, or glycolipids obtained from erythrocyte membrane in various pathological situations, the determination of the carbohydrate content of the whole membrane appeared a necessary preliminary. This study concerns the determination of the normal values of the main carbohydrates of whole human erythrocyte membranes, with respect to their blood group. Erythrocyte membranes were prepared from donors of the four ABO blood groups. After acidic hydrolysis, the contents of fucose, mannose, galactose, glucose, glucosamine, galactosamine and N-acetylneuraminic acid in each blood group were determined and compared with one another. The galactosamine content of A, B and AB erythrocyte membranes is significantly higher than that of the O-erythrocyte. For galactose, the differences are significant for the following pairs: A/O; B/O; AB/O; A/B; A/AB. Significant differences in the mannose contents of O-erythrocytes and A, B and AB erythrocytes have also been found. This result suggests that a basic difference, in the core of the oligosaccharide chains, may exist between O and A, B, AB erythrocyte membranes.

ABO Blood-Group System↗
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

[Detection of antigenic determinants of membranes using an insoluble peanut lectin].

The binding of lectins on insoluble supports may be used to detect the interactions occurring between these molecules and the sites of some receptors of membranes. An example is given, using the "anti-T" lectin extracted from peanut, to show the presence of determinants with terminal free glactose on the surface of erythrocytes and lymphocytes.

Arachis↗