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Biomedical subjects

D Raulais

Publications and source records attributed to D Raulais.

At least 37 records · Page 2Linked to original sources
PubMed1991

[A new family of proteins with high activity for heparin and regulated by retinoic acid].

An heparin binding protein (RIHB) was purified from chick embryos. Essentially expressed during early embryogenesis it is mainly localized within basement membranes. Its synthesis and that of the RIHB mRNA are induced by retinoic acid in chicken myoblasts cell culture. This protein belongs to the same family that HBGAM or Pleiotropin and MK protein two other heparin binding proteins exhibiting growth and/or neurotrophic activities.

Animals↗
PubMed1991

Heparin-binding sites of rat rhabdomyosarcoma cells with low and high metastatic capacity.

Proteins able to bind the iduronate containing glycosaminoglycans: heparin, heparan sulfate and dermatan sulfate, were detected in strongly (RMS 0) and weakly (RMS 8) metastatic rat rhabdomyosarcoma cell lines. The 35S-methionine-labeled proteins solubilized from the cell membranes were chromatographed on Heparin-Ultrogel affinity column. The main retained protein migrated with an apparent molecular size of 19 kDa on polyacrylamide gel electrophoresis from both cell lines. The 19 kDa protein exhibited a higher affinity for iduronate containing glycosaminoglycans than for the glucuronate containing chondroitin sulfates. It was immunologically distinct from acid and basic fibroblast growth factors. The membranes of the RMS 8 cells contained about a two times higher amount of labeled 19 kDa protein than the membranes of the RMS 0 cells. The decreased amount of the labeled heparin-binding proteins in the highly metastatic cell line is in agreement with the previously evidenced decreased receptor-mediated binding of the iduronate containing glycosaminoglycans by these cells.

Animals↗
PubMed1990

Basic fibroblast growth factor expression in human omental microvascular endothelial cells and the effect of phorbol ester.

The human omentum contains a potent, not yet identified angiogenic activity. The omentum is very vascularized. Therefore, we investigated whether human omental microvascular endothelial cells (HOME cells) express the angiogenic peptide basic fibroblast growth factor (bFGF). Cytosol prepared from HOME cells stimulated DNA synthesis in bovine epithelial lens cells (BEL cells). The mitogenic activity could be neutralized by an anti-bFGF antibody. Basic FGF-like material from the HOME cell cytosol was bound onto a heparin-Sepharose column at 0.6 M and was eluted at 3 M NaCl. The 3 M NaCl eluted material reacted with the specific anti-bFGF antibody in an ELISA and stimulated DNA synthesis. It did not react with a specific anti-acidic fibroblast growth factor (aFGF) antibody. Western blotting experiments using the same bFGF antibody showed the presence of a major band of 17 Kd and a doublet of 20-22 Kd. Northern blotting of non-stimulated HOME cells using a specific 1.4 kb bFGF probe showed the presence of 5 molecular species of 6.6, 3.7, 2.2, 2.0, and 1.0 kb. No aFGF mRNA was detected with a specific previously characterized 4.04 kb probe. 12-O-tetradecanoylphorbol 13-acetate (TPA) did not influence significantly the expression of bFGF at the protein and mRNA level in HOME cells. Thus, protein kinase C activation by TPA did not appear to modulate significantly the expression of bFGF for that cell type. Contrastingly, human umbilical vein endothelial cells (HUVE cells), which expressed no bFGF and aFGF mRNA at a basal level, were induced to express bFGF but not aFGF mRNA when stimulated by TPA. These results suggest that the described angiogenic activity could be the bFGF-like mitogen contained in HOME cells and that these cells are different from endothelial cells derived from large vessels (HUVE cells) regarding the expression of bFGF.

Biological Assay↗
PubMed1989

Identification of a new heparin-binding protein localized within chick basement membranes.

A protein with a molecular mass of 19 kDa has been purified to homogeneity from 11-day-old chick embryos using a procedure involving chromatography on heparin - Sepharose, immunoaffinity resin and C4 reversed-phase. Indirect immunofluorescence studies, using polyclonal and monoclonal antibodies raised against this protein, indicate that it is essentially localized within the basement membranes in early embryonic tissues. After the 18th day of embryonic life and in post-hatched chicken, this protein could only be detected in some eye basement membranes. It appears to be bound to heparan sulfate chains of the proteoglycan present in these structures. Thus, the protein exhibits similar properties to those previously described for fibroblast growth factors (FGF), such as heparin affinity, molecular mass and localization in the basement membranes. In contrast, this protein is present in much larger amounts than FGFs, at least in 11-day-old embryos. Furthermore, the first 17 amino acid residues of the N-terminal sequence show that it does not strictly correspond to any previously described protein.

Amino Acid Sequence↗
PubMed1989

Fibroblast growth factor phosphorylation and receptors in rod outer segments.

Acidic and basic fibroblast growth factors (aFGF and bFGF) have been isolated and purified from rod outer segments (ROS). aFGF is tightly bound to ROS membranes and can be specifically released by ATP. We show that this mechanism is dependent on the phosphorylation of aFGF itself. Phorbol 12-myristate 13-acetate (PMA) enhances this phenomenon independently of rhodopsin phosphorylation. This demonstrates that aFGF release from ROS membranes is dependent on its phosphorylation by endogenous kinase C. In addition specific binding sites for exogenous FGFs have been identified on ROS and disc membranes. A single high affinity site with a Kd of 40 pM was present in intact ROS while an additional low affinity site with a Kd of 300-600 pM was present in leaky ROS or in disc membranes. Light or ATP modified neither these Kd nor the apparent number of sites. The presence of specific receptors for FGFs and the kinase C dependent release of endogenous membrane bound aFGF suggest an autocrine mechanism which may be involved in photoreceptor cell biology.

Animals↗
PubMed1987

Characterization of acidic and basic fibroblast growth factors in brain, retina and vitreous chick embryo.

We have purified acidic and basic fibroblast growth factors (c-aFGF, c-bFGF) from 11 day-old chick embryo brain, retina and vitreous by heparin-Sepharose chromatography and reverse phase HPLC. The analysis of their biological activity as well as their molecular weight indicates that they were analogous to basic or acidic human and bovine FGF. The ratio of c-aFGF to c-bFGF activity depended of the tissue. In brain c-aFGF represented 66% of the total mitogenic activity retained on the heparin-sepharose column and c-bFGF 34% while retina contained 16% of c-aFGF and 84% of c-bFGF; vitreous 78% of c-aFGF and 22% of c-bFGF. Like human aFGF, Heparin stimulated purified c-aFGF mitogenic activity in the absence of serum but inhibited the activity of the retina acid soluble extract, in the presence of foetal calf serum (FCS). Thus, chick embryo and adult human acidic and basic FGF respectively share the same biochemical properties. Since there are no blood vessels in chick retina or vitreous, their presence in these tissues suggests that angiogenesis is not the only role of these growth factors.

Animals↗
PubMed1986

Oral immunization with a synthetic peptide of cholera toxin B subunit. Obtention of neutralizing antibodies.

The ability of free synthetic fragments of the cholera toxin (CT), administered by parenteral or oral route, without adjuvant, to induce antibodies cross-reacting with CT was tested. Two peptides corresponding to the sequences 30-50 and 50-75 of the CT beta chain were selected and synthesized. Both free peptides, given intraperitoneally or orally, without adjuvant, elicited seric antibodies cross-reacting with CT. The anti-(P50-75) antibodies were able to neutralize the CT activity. Our results show that protection against a toxin at the systemic level can be obtained with a synthetic peptide even when administered by an oral route.

Administration, Oral↗
PubMed1985

Epitopes of the 44-68 human parathyroid hormone fragments: the importance of specific hydrophilic peptide sequences.

Several pentapeptides included in the 44-68 sequence of human parathyroid hormone (hPTH) were synthesized simultaneously on benzhydrylamine and m-nitrobenzhydrylamine resins. The first polymer gave the free peptide and the second the peptidyl-resin complex. An ELISA test carried out with each peptidyl-resin complex showed that all the anti-44-68 hPTH antibodies raised in different animal species are directed against the same hPTH pentapeptidic sequence. This sequence is very hydrophilic and is specific to the hormone. This study demonstrates the importance of specific peptide chains in an epitope.

Amino Acid Sequence↗
PubMed1985

Solid phase synthesis of two cholera toxin B subunit antigens.

The 30-50 and 50-75 sequences of the cholera toxin beta chain including the amino-acids that are thought to be involved in toxin-receptor binding have been synthesized using the solid phase method. They were then purified by gel permeation and ion exchange chromatography. Both these free peptides induced serum antibodies recognising the native toxin after oral or intraperitoneal administration. Only the antibodies raised against the 50-75 peptide, however, were able to neutralize toxin activity.

Animals↗
PubMed1979

Immunochemical studies on rabbit calcitonin.

Cross reaction studies using radioimmunoassays specific for human and porcine calcitonin showed that rabbit calcitonin is structurally more closely related to human than to porcine calcitonin.

Animals↗
PubMed1976

The complete amino-acid sequence of rat thyrocalcitonin.

The complete amino acid sequence of rat thyrocalcitonin has been determined by automated Edman degradations of the intact molecule, a cyanogen bromide fragment, and by degradations of mixtures of peptides produced by hydrolysis of the hormone with trypsin and chymotrypsin. The sequence determined was H2N-Cys-Gly-Asn-Leu-Ser-Thr-Cys-Met-Leu-Gly-Thr-Tyr-Thr-Gln-Asp-Leu-Asn-Lys-Phe-His-Thr-Phe-Pro-Gln-Thr-Ser-Ile-Gly-Val-Gly-Ala-Pro-NH2. This sequence differs in only two positions from that found in the human hormone, i.e. leucine-16 in the rat vs phenylalanine-16 in the human, and serine-26 in the rat vs alanine-26 in the human. These similarities and differences are consistent with the previously reported immunological properties of the hormones isolated from these two species.

Amino Acid Sequence↗