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Biomedical subjects

R Bourrillon

Publications and source records attributed to R Bourrillon.

At least 19 recordsLinked to original sources
PubMed1992

Identification of peanut agglutinin receptors related to the state of tumoral liver cell differentiation.

The relationship between cell differentiation/tumorisation and plasma membrane glycoproteins was approached using peanut agglutinin (PNA) a lectin specific for the Gal-beta(1,3)GalNAc sequence and a homologous cell system consisted of normal rat hepatocytes (HyC) and a poorly differentiated hepatoma (ZHC). This work is focused on the molecular nature of PNA receptors. PNA bound strongly to ZHC, but bound very weakly, if at all to hepatocytes. After sialidase treatment this binding was slightly enhanced in ZHC and HyC. The total number of binding sites on ZHC was 9.6 x 10(6)/cell and 1.2 x 10(7)/cell before and after sialidase treatment respectively. In contrast, this number could not be calculated on HyC, even after sialidase treatment. The PNA receptors were isolated and identified from ZHC using affinity chromatography on immobilized PNA and lectin overlay. Two bands were revealed after SDS-PAGE of PNA receptors: a major one with a relative molecular mass of 160 kDa and a minor one of 110 kDa. The latter disappeared after sialidase treatment of ZHC suggesting the possibility that these two bands could be less and more sialylated forms of the PNA receptors, respectively. In contrast no PNA receptors could be detected on HyC. These PNA receptors could be considered O-linked glycoproteins containing the Gal-beta(1,3)GalNAc disaccharide because: i) PNA carbohydrate specificity toward this disaccharide found in this glycoprotein type; ii) their carbohydrate composition with Gal and GalNAc but not man residues; iii) their sensitivity to alkaline treatment; and iv) strong inhibition of PNA binding to ZHC with the Gal-beta(1,3)GalNAc structure. The absence of PNA receptors on HyC appeared to be related to the absence of this glycoprotein containing the disaccharide but not to the change or failure of glycosylation of the polypeptide chain of PNA receptors. The relationship between the presence of PNA receptors and differentiation/tumorisation phenomena as well as the mechanism that induced the expression of these receptors are discussed.

Animals↗
PubMed1991

Immunological screening of a glycoprotein antigen expressed by Zajdela ascites hepatoma cells on normal rat tissues and tumour cells.

Expression of the glycoprotein MII2 antigen originally identified in Zajdela ascites hepatoma cells was investigated in several normal rat tissues and in more or less differentiated tumours using biochemical and immunological approaches. SDS-polyacrylamide gel electrophoresis followed by fluorography or immunoblotting with an antiserum raised against the purified MII2 antigen revealed that this antigen was absent from normal liver cells. ELISA assays, indirect immunofluorescence and immunoprecipitation experiments using the same antiserum showed that this glycoprotein was not expressed in various normal tissues such as liver, spleen, lung, pancreas, intestine and stomach, but it was unexpectedly detected in kidney and thymic tissues. However, the molecular weight of the antigens immunoprecipitated from kidney and thymus was lower than the one of MII2 (Mr of 60,000 versus 110,000-160,000 for purified MII2). No staining was observed in embryonic rat liver at 10 and 20 days of development. Moreover, this antigen was present on the surface of Morris hepatoma 7777, another rapidly proliferating and poorly differentiated hepatocellular carcinoma. In contrast, this antigen was not detected on the surface of in vitro Zajdela hepatoma cells (ZHC) or of partially differentiated hepatomas (Faza) which have recovered some hepatic functions. In addition, the MII2 antigen was found on the human non-hepatic HT-29 tumour cell line, under its undifferentiated form (HT-29 G+ subline). The possible relationships between the expression of this antigen and both the malignant transformation process and the differentiation process are discussed.

Animals↗
PubMed1979

Changes in the sensitivity of chick fibroblasts to Ricinus lectin (RCA I) toxicity in relation to the stage of embryo development.

The toxic effect of Ricinus lectin RCA I, as estimated by the inhibition of [3H]leucine incorporation, was investigated on chick-embryo fibroblasts at different stages of development. There appeared to be a differential susceptibility of chick-embryo fibroblasts to lectin RCA I. Fibroblasts from 16-day embryos were the most sensitive to its toxic effect in terms of both concentration and time, and cells from 8-day embryos were the least sensitive. This differential sensitivity to the toxic effect of lectin RCA I was closely related to the binding of the lectin: fibroblasts from 16-day embryos had more binding sites (1.5 x 10(7)/cell) with a high affinity than did 12-day (0.45 x 10(7)/cell) or 8-day embryos (0.2 x 10(7)/cell). Studies on the specificity and the removal of bound lectin RCA I by D-galactose indicated that the lectin binding was necessary but not sufficient in itself to cause the toxic effect and that the lectin needed to enter the cells in order to be toxic. The amount of lectin RCA I needed to induce a 50-60% toxicity enters fibroblasts of 16-day embryos more rapidly than those of 12- and 8-day embryos.

Animals↗
PubMed1979

[Fucosidosis and blood group substances in the urine].

Glycopeptide and oligosaccharide fractions obtained from fucosidosis urine contains more Lea activity (4-8 fold) than control urine. Both fucosidosis fractions also contained Leb and H activities, no A activity in contrast to the salivary and erythrocyte phenotypes (A, Le a+ b-). The amount of Leb activity is lower in both fractions (1) and (2) than that of Leb control children (4-16 fold decrease). Blood group A activity was not detected at any concentration used (less than or equal to 50 fold-concentrated urine) whereas A activity was found in (A, Le a- b+) control urine. On the contrary, both fucosidosis fractions contained H activity, whereas A (Le a- b+) control children fractions had none (less than or equal to 50-fold concentrated urine). H and Leb activity might originate from Lea precursor apart from the "non-secretory" type of the patient.

Blood Group Antigens↗
PubMed1979

[Electrophoretic profiles of proteins and glycoproteins of chick embryo fibroblasts during development].

The variations of proteins and glycoproteins of Chick embryo fibroblasts are studied during development. This investigation is carried out using polyacrylamide disc gel electrophoresis in SDS. Two glycoproteins of high apparent molecular weight (250,000 and 200,000) undergo quantitative modification: they increase from the 8th to 12th day of development and then remain unchanged to the 16th day. They are cell surface components as suggested by fluorescamine labelling and trypsin sensitivity. The results are discussed in terms of relationship between tumor- and embryo cells.

Animals↗
PubMed1979

[Interaction between ricin hemagglutinin and its ligands, galactose and lactose. Microcalorimetry and equilibrium dialysis].

The interaction of Ricinus communis hemagglutinin with galactose and lactose has been studied by means of microcalorimetry, equilibrium dialysis and analytical ultracentrifugation. A first class of beta-galactoside-binding sites involves two similar and independent sites of which affinity constants are 2600 M-1 for galactose and 26700 M-1 for lactose at 25 degrees C. The binding of one galactose or one lactose molecule leads to enthalpy changes of--12.3 Kcal and--11 Kcal, respectively. Considering the negative entropy changes of the association, and as for ricin, the binding of galactosides with hemagglutinin is driven by favorable enthalpic contributions. In presence of high lactose concentrations, a second endothermic step of the calorimetric titration curve was observed. This result and the biphasic nature of Scatchard plots of equilibrium dialysis suggest the existence of a second class of binding sites on the lectin molecule. As for ricin, the interaction between these secondary sites and lactose would be entropically driven.

Agglutinins↗
PubMed1979

Interaction between the Ricinus sanguineus agglutinin and receptor sites isolated from normal human lymphocytes.

Solubilized surface proteins from normal human lymphocytes were obtained by mild trypsin digestion. The binding of membrane components to labelled Ricinus sanguineus agglutinin (molecular weight = 120,000 daltons) was studied by a gel filtration method. The bound and unbound lectin amounts were determined from the gel filtration patterns. The binding parameters were calculated from Scatchard plots. They were compared to the parameters obtained at the same temperature for the lectin-intact lymphocyte system. The respective values for the affinity constant, were 3.5 x 10(6) M-1 and 6 x 10(6) M-1. The calculation of the number of sites per cell in each system specifies the yield of the trypsin digestion.

Cell Membrane↗
PubMed1979

Concanavalin A binding to amphibian embryo and effect on morphogenesis.

The effect of Concanavalin A (Con A) on morphogenesis in Pleurodeles waltlii has been studied. Embryos were incubated with various concentrations of the lectin for a period of 6 days. Three stages of development were examined, late blastula, young gastrula and late gastrula. In the presence of the lectin at a concentration of 200, 150 or 100 micrograms/ml morphogenic movements were delayed, altered and finally blocked. At lower concentrations, 50 or 25 microgram/ml, there was a slight delay in gastrulation, but in some cases development was normal. These findings indicate that Con A exerted an inhibitory effect on amphibian morphogenesis and there is evidence that the lectin effect was concentration dependent. The effects of Con A were specific since they were totally inhibited by alpha-methyl-D-mannopyranoside (0.05 M). The viability of the 24 h lectin-treated embryos was demonstrated by washing experiments. Labelled Con A binding to the embryos was investigated before and after discarding the vitelline membrane. The results suggest a direct interaction between Con A and the cell surface and this was confirmed by using fluorescein isothiocyanate Con A.

Animals↗
PubMed1978

Binding of galactose and lactose to ricin. Equilibrium studies.

The interaction of ricin, one of the two lectins of Ricinus sanguineus, with its specific ligands galactose and lactose (4-O-beta-D-galactopyranosyl-D-glucopyranose) has been studied by means of equilibrium dialysis, analytical ultracentrifugation and fluorescence polarization. In the studied concentration range, only one molecule of galactose is bound per molecule of ricin with an association constant, Ka = 6900 m-1 at 4 degrees C. Scatchard plots of equilibrium dialysis data show that two molecules of lactose bind to one molecule of ricin, without modification of molecular weight of the lectin. Together with results of microcalorimetric experiments and agglutination of erythrocytes by ricin, equilibrium dialysis data indicate that the lectin contains two distinct saccharide binding sites. Regardless of the existence of extended sites, it is not possible to select between the two models: (a) two independent sites (Ka1 = 35 000 M-1, Ka2 = 2800 M-1 at 4 degrees C) or (b) two identical sites with negative cooperativity.

Dialysis↗
PubMed1978

[Excretion of sialoglycopeptides in mucolipidosis I].

Mucolipidosis I involves a tremendous increase of the urinary excretion of sialoglycopeptides and sialyloligosaccharides. This enhancement is due to the excretion of O- and N-glycosidic peptides and oligosaccharides, which normal urine is devoid of as shown by the chemical composition and electrophoresis or thin-layer analysis. This finding is in agreement with the recent finding of an alpha-neuraminidase deficiency for this disease.

Child↗
PubMed1978

Relationship between regeneration of cell surface glycoproteins in trypsin-treated chick embryo fibroblasts and cell adhesion to the substratum.

The ability of cells to adhere to a substratum was altered by treatment with trypsin but was restored after a 1.5-h culture. A concomitant incorporation of [3H] leucine and [14C] glucosamine in the trypsin-sensitive cell surface glycoproteins was observed and almost reached a plateau within 1.50 h following the treatment with trypsin.

Cell Adhesion↗
PubMed1978

Specific modifications of hepatoma cell-surface glycoproteins with enzymes. Effects on in vitro growth as investigated by the use of lectins.

The effects of enzymic treatment on the interactions between Zajdela's tumor cells and various lectins. Concanavalin A (ConA); Wheat Germ Agglutinin (WGA); Robinia lectin; have been studied. (1) The number of lectin-binding sites and the affinity constants were investigated. (2) The effects of the lectins on cell growth and [3H]thymidine incorporation were studied on untreated and enzyme-treated cells. It was observed that treatment of tumor cells with neuraminidase resulted in a change in the binding characteristics of each lectin. However, additional treatment of the cells with galactose oxidase had no further effect on lectin binding. ConA and Robinia lectin induced a decrease of the untreated tumor cell growth and a stimulation of the [3H]thymidine incorporation. This paradoxal result may be explained as a consequence of the stimulation of the [3H]thymidine uptake observed in the presence of lectins. The enzymatic treatments themselves did not change the cell growth although they did induce a change in the effect of ConA and Robinia lectin on cell growth and [3H]thymidine incorporation. As a result of neuraminidase treatment, the effects of ConA were totally suppressed but those of Robinia lectin only partially. Although WGA interacted with untreated and enzyme-treated cell surfaces, it had no effect on tumor cell growth nor [3H]thymidine incorporation. The results are discussed in terms of lectin transport.

Animals↗
PubMed1978

Modifications of lectin binding on human leukemic cells after neuraminidase treatment.

Cell surface modifications after vibrio cholerae neuraminidase treatment were investigated using three different tritiated lectins: Concanavalin A, Ricinus sanguineus agglutinin (R.S.A.) and Robinia pseudoacacia lectin. Lectin binding measurements were performed on untreated and enzyme treated cells. The cells used were from chronic and acute leukemic donors. After neuraminidase treatment, a significant increase in the number of receptor sites, from 1 to 3 times, was found in all cases tested and for all three lectins utilized with only one exception. The affinity constant was generally decreased after neuraminidase treatment. The increase in number lectin binding sites, indicating extensive modification of the cell surface, is completely consistant with the known importance of sialic acid in determining immunogenicity.

Binding Sites↗
PubMed1978

Activation of human B lymphocytes induced by Robinia pseudoacacia lectin in the presence of T cells.

Robinia pseudoacacia seed lectin is a potent human lymphocyte activator which is capable of activating pure T cells but not pure B lymphocytes. However, when B and T cells were cultured together, the thymidine incorporation was found to be higher than that expected from B- or T-cell cultures alone. Killing of T cells by anti-human-T-lymphocyte antigen (HTLA) serum and complement at the time of thymidine incorporation was found to be unable to suppress completely the thymidine uptake whereas treatment by anti-human-B-lymphocyte and monocyte antigen (HBLMA) serum reduced the response to some extent. Moreover, stimulated lymphoblasts were shown to bear B-cell markers (surface Ig and complement receptors) in about the same proportion as B lymphocytes present in the cultures. These results show that B cells proliferate in the presence of T cells and Robinia lectin. Finally, activation of B cells by Robinia lectin in the presence of T cells led to their maturation to plasma cells in the same way as PWM.

Antilymphocyte Serum↗
PubMed1978

Sialic acid-containing glycoconjugates in human lactation urine.

The excretion rate of neutral hexoses, fucose and sialic acid of oligosaccharide and glycopeptide fraction has been determined in lactation urine. Thin layer chromatography has been used to investigate the excretion pattern of oligosaccharides, specially sialyl-oligosaccharides, during the course of lactation and after weaning. Lactation urine contains sialyloligosaccharides which are not present in normal urine and their presence has been studied up to the 3rd week after weaning. These results indicate a mammary origin for most of these compounds and confirm the hypothesis of previous research.

Female↗