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B Delpech

Publications and source records attributed to B Delpech.

At least 109 records · Page 6Linked to original sources
PubMed1984

Expression of hyaluronic acid-binding glycoprotein, hyaluronectin, in the developing rat embryo.

Immunological and histological methods have been applied to the developing rat embryo to study the distribution of hyaluronectin (HN, a glycoprotein with hyaluronic acid-binding properties) previously shown to be present in the nervous system and in desmoplasias. HN was absent in the morula and the blastula and was first detected in the mesenchyme bordering the neural tube and somites on Day 10, i.e., at a time when hyaluronic acid is already widely dispersed in the mesenchyme. At this stage HN appeared to be closely associated with the basement membrane around the epithelial structures (somites, notochord, ectoderm) whereas the intercellular areas of mesenchyme were less strongly strained. The delineation of basement membranes decreased progressively, while the accumulation of HN increased in the cell-free areas of mesenchyme, giving a continuous, diffuse pattern. Differentiation of mesenchyme into vertebral cartilage and gut smooth muscle was accompanied by a progressive disappearance of HN. Even after streptomyces hyaluronidase or chondroitinase digestion the antigen was not unmasked in these tissues. The results are in agreement with the few observations made in the human. They suggest that HN could play a role, in association with fibronectin and glycosaminoglycans (hyaluronic acid), in the physiology of the embryonic extracellular matrix. HN appeared at a later stage in the embryonic nervous tissue; its distribution was extracellular in areas where both cell migration and proliferation occur.

Animals↗
PubMed1984

[Histologic characterization of hyaluronic acid in the cerebellum with hyaluronectin].

Two techniques of affino-immunofluorescence were described to localize hyaluronic acid (HA) on Rat cerebellum tissue sections. The first technique used the direct soluble hyaluronectin (HN)/anti-HN immune complex fixation to tissue-HA. In the second technique, HN fixation was followed by anti-HN antibody binding to HN. Both reactions were blocked by the addition of HA to HN/anti-HN complexes or to HN. The first direct technique is less time consuming and gives more clear-cut results than the second technique. These affino-immunological methods provide a better tool to localize HA in tissues than the classical stainings.

Animals↗
PubMed1984

[Production of monoclonal antibodies against gliofibrillary acid protein (GFAP) and their specificity].

Splenic Mice cells immunized with glial fibrillary acidic protein (GFAP) were fused with SP 2/0 myeloma cells. After screening and cloning we obtained two types of hybridomas. Some of them secrete IgG class antibodies, the others IgM class antibodies. The specificity of these antibodies has been tested by three immunoenzymatic methods. The results are that IgG monoclonal antibodies identify an astrocyte-GFAP specific epitope and IgM monoclonal antibodies cross-react with a common epitope to GFAP and vimentin.

Animals↗
PubMed1983

Localization of hyaluronectin in oligodendroglial cells.

Astroglia and oligodendroglia in primary cell cultures were identified by immunohistochemical staining with antiglial fibrillary acidic protein and anticerebroside antisera, respectively. The antiserum to hyaluronectin (HN) was utilized to show that this hyaluronic acid-binding glycoprotein was localized in the oligodendroglial cels. This is consistent with the recent finding that HN is localized in the node of Ranvier. Astroglia did not react with antihyaluronectin.

Animals↗
PubMed1983

[Glial fibrillary acidic protein and central nervous tumors. Immunohistochemical study of a series of 207 cases. 1: Astrocytomas. Glioblastomas. Ependymomas. Papillomas of the choroid plexus].

The presence of glial fibrillary acidic protein (GFA) was tested in biopsy or autopsy specimens of 207 human central tumors. Samples were fixed, paraffin-embedded and GFA was detected using the peroxidase-antiperoxidase technic. The first part of this study dealt mainly with glioblastomas (36 cases) and astrocytomas (87 cases). Tumors were classified in three categories according to their histological grade: 24 astrocytomas grade I and II, 63 astrocytomas grade III and IV and 36 glioblastomas (grade IV). For each of these tumors GFA positive cells were counted in 5 different fields using objectives of 2,5, 10 and 25. The results were as follows: less than 50% GFA positive cells were found in 22 out of 24 low grade astrocytomas, 49 out of 63 high grade astrocytomas and 32 out of 36 glioblastomas. Conversely, over 50% GFA positivity was found in 2 benign astrocytomas, 14 malignant astrocytomas and 4 glioblastomas. In 3 high grade tumors (2 astrocytomas, 1 glioblastoma) GFA positivity was found to be over 75%. Of the 17 ependymomas, 14 were GFA positive; however, no correlation could be established between the degree of GFA positivity and histological grade. The three papillomas of the choroid plexus of the lateral ventricles found in children were GFA negative. In adults, a GFA positive focus of ependymal differentiation was found in a papilloma of the choroid plexus in the posterior cerebral fossa.

Adult↗
PubMed1983

[Glial fibrillary acidic protein and central nervous system tumors. Immunohistochemical study of a series of 207 cases. 2: Medulloblastomas. Hemangioblastomas. Other tumors. Discussion].

The presence of glial fibrillary acidic protein (GFA) was tested in biopsy or autopsy specimens of 207 human central nervous system tumors. Samples were fixed, paraffin-embedded and GFA was detected using the peroxidase-antiperoxidase technique. The second part of this study dealt mainly with medulloblastomas and hemangioblastomas. Of the 17 cerebellar medulloblastomas, 15 contained less than 5% GFA positive cells. These were classified according to the Mannoji et al., 1981, criteria. Ten medulloblastomas contained type 1, 2 and 3 cells; 1 was composed of only type 1 cells, and 4 were composed of only type 3 cells. Of the 8 cerebellar or medullary hemangioblastomas, 3 contained only a few GFA positive cells which were, in two cases stroma cells and in another, astrocytes. GFA positive cells were found in 7 oligoastrocytomas, 3 gangliogliomas and 1 hamartoma of the hypothalamus. Similarly, a GFA positive astrocytic differentiation was found in a pineocytoma. In a case of tuberous sclerosis no GFA was found in the giant cells of cortical tubers. Nor was GFA observed in one intracerebral tumor of tuberous sclerosis. GFA was not found in 5 meningiomas, 4 oligodendrogliomas, 4 pituitary adenomas, 3 neurinomas of the VIII cranial nerve, 1 primary cerebellar malignant lymphoma, 1 familial lymphohistiocytosis with cerebellar involvement and 4 brain metastases. The authors also include diagnostic, histogenetic and nosological comments -about neuroglial tumors. The findings in the two parts of this study fail to establish a correlation between GFA positivity and histological grade of astrocytomas and glioblastomas.

Adult↗
PubMed1983

[Determination of immunoglobulins A in the fluids of normal human intestinal perfusion].

Immunoglobulin A (IgA) in intestinal secretions is present in several molecular forms among which dimeric IgA linked to the secretory component (S-IgA) predominates. IgA was measured in jejunal perfusates obtained in nine normal subjects by intraluminal perfusion under a proximal occluding balloon of an isotonic and non antigenic solution. The method associated reverse radial immunodiffusion technique or nephelometry, using human serum as standard with chromatography on a polyacrylamide indubiose column. Chromatography separated IgA between two fractions whose elution ratios were the same as those found with mixtures of pure monomeric IgA and S-IgA. A scale was constructed from the latter, allowing the calculation of the percentages of monomeric IgA and S-IgA present in the jejunal perfusates, and that of their total content of IgA.

Chromatography↗
PubMed1982

Localization of hyaluronectin in the nervous system.

The localization of hyaluronectin was determined by immunofluorescence and immunoperoxidase methods, in the rat, the sheep and the human. The study of the peripheral nervous system revealed the localization of this protein at the node of Ranvier. It was also present at this site in the central nervous system where the appearance was less characteristic than in the peripheral nervous system. The protein was also observed around about 10% of neurones in all of the regions studied. The subcellular structures labelled could not be precisely defined with the optical microscope.

Animals↗
PubMed1982

Hyaluronectin in normal human skin and in basal cell carcinoma.

The localization of hyaluronectin has been studied in normal skin and in basal cell carcinoma. In fetal skin it is abundant in the dermis but absent from the epidermis, and in adult skin it is totally absent except in the hair sheaths and bulbs. In basal cell carcinoma it is abundant only in the stroma reaction. The presence of this protein in mesenchymatous tissues seems to be linked to zones of physiological or neoplastic proliferation.

Adult↗
PubMed1982

Immunochemical characterization of the hyaluronic acid-hyaluronectin interaction.

The interaction between hyaluronic acid (HA) and hyaluronectin (HN) was analyzed by gel chromatography and by the effects of HA on the immunological precipitation of HN. This interaction led to formation of larger molecules, as shown by gel permeation. No inhibition of immune precipitation occurred in liquid phase after addition of HA, but the precipitates in unstained gels were rendered transparent, giving the appearance of inhibition. However, after staining of the gels the precipitates appeared normal. Moreover, a non-linear decrease of the diffusion rate in antibody-containing gel was observed as a function of HA concentration at HA:HN weight ratios of 0.75 x 10(-3) and higher. A faster movement during electrophoresis, depending on the HA:HN ratio, suppressed the precipitation line when tested by electrosyneresis and produced an increase in migration distance when tested by Laurell's electroimmunoassay. These results show that in the immunochemical detection and quantitation of NH by these techniques consideration should always be given to the amount of HA in the samples.

Brain Chemistry↗
PubMed1982

Characterization of hyaluronectin in human tumour heterografts in the nude mouse.

Three established cell lines derived from three human astrocytomas were grafted into nude mice. Hyaluronectin, a marker of loose connective tissue, was detected in the grafts. The histopathology and the hyaluronectin staining were similar to those of the tumours of origin. Absorption experiments demonstrate that one of the three human grafted tumours (CB 109) contains a human type hyaluronectin, in contrast to the other two. In these two grafts, hyaluronectin is a constituent of the host stromal reaction, whereas in the CB 109 graft hyaluronectin apparently originates from the human tumour cells. This tumour could be used to test the production of human hyaluronectin in vitro and in vivo.

Animals↗
PubMed1982

Inhibition of active E rosette forming T lymphocytes by hyaluronic acid. Evidence of a receptor for hyaluronic acid on a lymphocyte subpopulation.

Previous studies have shown the inhibition of active E rosette forming T lymphocytes by a mesenchyme associated antigen. Recent results clearly indicated that this antigen consisted in the association of a glycoprotein named hyaluronectin with hyaluronic acid. Using the active E rosette technique of Wybran and Fudenberg, we have studied the action of hyaluronic acid on T lymphocytes. We obtained evidence of the partial inhibition of active E rosette formation by hyaluronic acid in 19 of 25 healthy subjects. Among them, inhibition percentage was 45 +/- 4. This inhibition remained significant at a concentration of 22.5 micrograms/ml hyaluronic acid. Hyaluronic acid was labelled with peroxidase by the glutaraldehyde technique: 17 +/- 7% lymphocytes were stained by this preparation. The preincubation of peroxydase labelled hyaluronic acid by brain hyaluronectin lowered this staining. This is in agreement with the presence of hyaluronectin on a subpopulation of lymphocytes as it was shown by immunofluorescence techniques. In conclusion, a receptor for hyaluronic acid (hyaluronectin) was detected on a proportion of lymphocytes. These results suggest that hyaluronic acid could have an immunosuppressive activity.

Humans↗
PubMed1981

[Trials of in vitro propagation of the scrapie agent in mouse nerve cells].

We attempted to propagate the Scrapie agent in vitro in glia and neuroblastoma cells of Mice. Four out of seven assays of infection were positive, i.e. after several passages in vitro yielding at most a 10(9) fold final dilution of the original material, the extracts of each of the four cultures, when injected intracerebrally into CD1 Mice, produced a deadly disease displaying the clinical and pathological signs characteristic of Scrapie.

Animals↗
PubMed1981

Characterization and purification from human brain of a hyaluronic acid-binding glycoprotein, hyaluronectin.

Using affinity chromatography and enzyme-labelled immunological assays combined with affinity adsorption, we have obtained evidence for the binding of a brain glycoprotein to hyaluronic acid, and on this basis named it hyaluronectin. This binding was inhibited by hyaluronic acid and by the products of its hydrolysis by hyaluronidase from bovine testis, but was not inhibited by other glycosaminoglycans or by monosaccharides. Preparative affinity chromatography of brain acid-soluble proteins produced hyaluronectin in a good degree of purity. Contamination by albumin was less than 1% and the yield was as high as 80%.

Binding, Competitive↗
PubMed1981

Assessment of the accuracy of segmental perfusion under an occluding balloon for measuring the intrajejunal secretion of albumin and immunoglobulin A.

The suitability was investigated of the segmental perfusion technique under an occluding balloon (which prevents the contamination of the test segment by upper digestive secretions and pancreatic proteolytic enzymes) for measuring immunoglobulin A (IgA) and serum albumin outputs into the jejunal lumen. The influence of the perfusion rate and of the transintestinal water movements in the 40 cm long test segment was studied in 11 healthy subjects. IgA and serum albumin outputs did not differ significantly when the same isotonic solution was perfused at rates of 5 or 10 ml/min, nor when water absorption was stimulated by the presence of glucose. A possible artefact linked to intestinal wall distension by the occluding balloon was evaluated in eight subjects with complete exocrine pancreas insufficiency. IgA and serum albumin outputs obtained under the occluding balloon were compared with those found with the triple non-occlusive method. Care was taken to achieve a similar flow rate and solute composition of the fluid entering the test segments with both techniques in each subject. Under these conditions, IgA and serum albumin outputs measured with both methods did not differ significantly. These findings validate the use of the segmental perfusion technique under an occluding balloon to measure IgA and serum albumin outputs into the human small intestine.

Adult↗
PubMed1981

[Nervous system tumour proteins. G.F.A. and hyaluronectin (author's transl)].

G.F.A. (gliofibrillary acid protein) and hyaluronectin studied here are two antigens defined by the heteroantibodies which appear in the serum of the immunised animal. G.F.A. is associated with gliofilaments and is considered as an astrocyte marker, either normal or tumoral. Hyaluronectin, is found in the Ranvier nodes and at the periphery of neurones. It is not specific to the nervous system. It is found in all tissues and tumors, and in particular marks the intercellular spaces of gliomas, where it is associated with hyaluronic acid for which it has a great affinity. Serum estimation of these Proteins is being undertaken with the view to a clinical application.

Animals↗