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Biomedical subjects

A Delpech

Publications and source records attributed to A Delpech.

At least 37 records · Page 2Linked to original sources
PubMed1993

Expression of the hyaluronan-binding glycoprotein hyaluronectin in leukemias.

Hyaluronectin (HN), a hyaluronan (hyaluronic acid, HA)-binding glycoprotein is normally expressed in the nervous system, found in the desmoplasia of tumours, and is also produced in vitro by peripheral blood mononuclear cells. We have therefore investigated the expression and the production of HN by leukemic cells, with the hypothesis that HN would be expressed in leukemias of the myeloid lineage. Fresh and frozen leukemic cells were studied from 70 patients of whom 53 had acute myeloblastic leukemia (AML). HN was strongly expressed (> 80% blood cells) in two out of 13 M4 AMLs and four out of four M5B AMLs. One further M4 AML displayed 25% positive cells and two 20% cell positivity cases were seen, in one case of M4 AML and in one case of chronic myelomonocytic leukemia (CMML). The rest of the cases of AML as well as all cases of acute lymphoblastic leukemia (ALL) showed almost no positivity (< 1%). The residual positive cells appeared to be normal blood promonocytes. Taken together > or = 20% positive cells was seen in eight out of 56 (14%) examined myeloid leukemias. The HN production was significantly higher (p < 0.0001) in cell culture media of M4 and M5 AML cells than in other AML or ALL cell culture media. A significant correlation was found (p < 0.0001) between the number of HN-positive leukemic cells and the number of cells with a monocytic morphology, suggesting that HN is a marker for the promonocyte.

Acute Disease↗
PubMed1992

Staining of hyaluronan in rat cerebellum with a hyaluronectin-antihyaluronectin immune complex.

The presence of hyaluronan was studied histochemically in the adult rat cerebellum. We used the hyaluronectin--antihyaluronectin immune complex technique based on the high affinity of hyaluronectin for hyaluronan. The immune complex was prepared with hyaluronectin from a human brain extract and an anti-hyaluronectin monoclonal antibody, which does not react with rat hyaluronectin. This is a specific probe for detecting hyaluronan in rat tissues without any reaction for tissue hyaluronectin. Hyaluronan was found at the nodes of Ranvier, in the perineuronal microenvironment of the deep nuclei and at the Purkinje cells surrounding the initial segment of the axon. It was located at the same places as hyaluronectin, in areas specialized in ion exchanges and neurotransmission. This suggests that the hyaluronectin-hyaluronan complex could be involved in these processes. The immune complex technique with anti-hyaluronectin monoclonal antibody thus seems to be a specific and valuable tool for investigations of the distribution of hyaluronan in the rat cerebellum.

Animals↗
PubMed1992

Production of a human monoclonal anti-epithelial cell surface antibody derived from a patient with pemphigus vulgaris.

The production of monoclonal autoantibodies derived from individuals with autoimmune diseases constitutes a powerful tool to analyse an autoimmune process at both the antigen and antibody levels. We established a human anti-epithelial cell surface monoclonal antibody by applying hybridoma technology using peripheral blood lymphocytes from a patient with pemphigus vulgaris using a heteromyeloma as the fusion partner. The F12 monoclonal antibody displays four major characteristics: (1) it belongs to the IgM, kappa class; (2) it binds to the cell surface of stratified squamous and simple epithelia; (3) it recognizes an antigenic determinant associated with the desmosomal complex as demonstrated by indirect immunoelectron microscopy; (4) by immunoblotting analysis, it reacts with a 185 kDa polypeptide which was also recognized by a few pemphigus vulgaris sera. Although the F12 monoclonal antibody does not have the immunochemical properties of classical pemphigus vulgaris autoantibodies, several arguments suggest its relevance to the pemphigus vulgaris autoimmune response and, therefore, the heterogeneity of the antigen/antibody systems involved in this autoimmune disorder.

Adolescent↗
PubMed1991

Characterization of a hyaluronic acid-binding protein from sheep brain comparison with human brain hyaluronectin.

1. A hyaluronic acid (HA)-binding glycoprotein from sheep brain was characterized. 2. The specific affinity for HA was shown in vitro by high performance liquid chromatography, polyacrylamide gel electrophoresis and ELISA methods. 3. The KD for high molecular weight HA was 5.4 10(-9) M at 37 degrees C and lower than 10(-10) M at 4 degrees C. 4. No link protein was found and HA molecules could bind up to 10 times their weight of the glycoprotein. 5. The specific site for interaction was the HA-derived decasaccharide HA10. 6. The protein is composed of one polypeptidic chain. Tryptophan and lysine play a prominent role in the conformation of the binding site to HA. 7. Enzyme analysis indicated that the protein different forms are due to differences in glycosylation and that N- and O-linkages coexist in the molecules. 8. Immunohistochemistry localized the glycoprotein at the nodes of Ranvier and at the periphery of neurons. The perineuronal labeling was seen around all neurons studied in the cerebellum whereas it was almost undetectable in the cerebral hemispheres. 9. HA is not saturated by hyaluronectin (HN) in the sheep nervous system. 10. The glycoprotein is largely similar to human brain HN, and different from the hyaluronate-binding protein characterized in the cartilage.

Amino Acid Sequence↗
PubMed1991

Anti-myeloperoxidase antibodies: immunological characteristics and clinical associations.

Antibodies directed against myeloperoxidase (anti-MPO) were detected, using a solid-phase ELISA and purified sputum myeloperoxidase as the substrate, in 54 sera from 22 patients. Anti-MPO were present in 17 patients with crescentic glomerulonephritis (CGN), Wegener's granulomatosis (WG) and microscopic polyarteritis (MPA), and thus are associated with different forms of vasculitis. Anti-MPO were also present in five out of 20 patients with systemic lupus erythematosus (SLE). Anti-MPO activity in SLE sera was low, in contrast to the high titers observed in patients with vasculitis. All positive sera had IgG anti-MPO (except two SLE sera) and most of them also contained low-titered IgM anti-MPO. Only three patients had high IgM anti-MPO activities, the significance of which remains to be determined. In patients with CGN, WG or MPA, the anti-MPO titer decreased following therapy and paralleled the disease activity. Thus, anti-MPO constitute a useful diagnostic tool and a sensitive marker of disease activity in this group of patients with vasculitis.

Arteritis↗
PubMed1990

Concentration of hyaluronectin and anionic glycoconjugates in perineuronal glial cell processes at GABAergic synapses of rat cerebellum.

Hyaluronectin was detected in the rat cerebellum using monospecific polyclonal antibodies at the light and electron microscopic level. The immunoreactivity was associated in the grey matter with glial (astrocytic) cell processes of perineuronal glial sheets but could not be found in glial cell bodies nor in neurons. This molecular specialization of grey matter astrocyte expansions was distinctly expressed at known sites of GABAergic synaptic transmission.

Animals↗
PubMed1989

Hyaluronan and hyaluronectin in the nervous system.

Hyaluronan was studied in extracts of the nervous system and in situ. Extraction yielded larger amounts at neutral or alkaline pH. Protease digestion enhanced the quantitative results obtained with an indirect enzyme immunological assay. It was shown that HA extracted from brain at neutral pH was bound to a glycoprotein component (hyaluronectin, HN) which is in part free at acid pH. Although HN is not restricted to nervous tissue it is mainly expressed in the central nervous system of adult mammals. Its main form has a molecular mass of 68 kDa and binds in vitro to HA and to HA-derived oligosaccharides down to HA10 with a Kd in the 10(-8) M range. HA-HN complexes were found in human cerebrospinal fluids. The HA concentration in cerebral tissue decreases from the fetus to the adult, whereas the HN concentration increases. HA is not however saturated by HN and still binds HN in vitro. In the rat HA decreases sharply at Days 10-11 after birth. In the rat embryo HA forms an extracellular component of the migration and proliferation areas of the cerebral cortex. In the adult typical locations were at the nodes of Ranvier and in perineuronal structures. HN was found in the same locations but seemed to be associated with a restricted category of neurons. In the cerebellum HA-HN was found mainly in the grey nuclei, the granular layer and around Purkinje cells. Cell bodies were not stained but in the electron microscope HN was seen in the cytoplasm and plasma membrane of the perisynaptic glial cell processes. A hypothesis has been proposed that HA-HN is involved in neural GABAergic transmission.

Brain↗
PubMed1989

[Latent and postpartum thyroiditis. Prospective study].

Thyroid evaluation was performed in 85 women at childbirth, then between 2 and 7 months, and 14 months later. Transient subclinical hypothyroidism was found in one woman; antithyroid antibodies were found in 10 and were persistent in 6, suggesting a late thyroiditis. For these 6 cases, 5 HLA typing showed 3 Locus DR4. The proportion of antithyroid antibody was the same in a reference population. This finding would be in agreement with the hypothesis of a latent thyroiditis, revealed by pregnancy. Relative iodine deficiency in France could explain the low frequency of post partum thyroiditis in the present study.

Female↗
PubMed1987

[Immunocytochemical demonstrating of a neurofibrillary component of the peripheral nervous system manifested by a human natural antibody].

Human serum SH2172, obtained from a girl suffering from bullous dermatosis, showed a natural immunoreactivity against the peripheral nervous system (PNS) of rat, mouse and hamster. Immunocytochemical staining and examination by light and electron microscopy demonstrated an intracellular neurofibrillary network localized in neurites and neuronal pericaryons. Comparative testing clearly showed that SH2172 immunoreactivity is different from that of the antibodies against the triplet of proteins NFP70, 160 and 200 kD. This unique serum should be a useful probe to study PNS neurocytoskeleton.

Adolescent↗
PubMed1986

Characterization of hyaluronic acid on tissue sections with hyaluronectin.

An affinity immunological procedure for hyaluronic acid detection on tissue sections is described. This new, sensitive, and specific technique is based on the high affinity of hyaluronectin for hyaluronic acid, utilizing anti-hyaluronectin-hyaluronectin immune complexes. Elimination of binding when the reagent was supplemented with hyaluronic acid or when Streptomyces hyaluronidase-digested tissue sections were used emphasizes the specificity of the assay. This technique made possible accurate HA localization in embryonic mesenchyme, in neural tissue, in kidney medulla, and in tumors.

Antibodies↗
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↗
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

[In vitro modification of the morphology and the growth of cells infected with scrapie (author's transl)].

Seven cell lines originated either in brains or in neuroblastomas of Mice, were infected with Scrapie. After 12 to 16 in vitro passages, 6 lines out of 7 showed changes of their morphology, and of their growth, resembling those occurring in the course of a malignant transformation. The Scrapie infected cells acquired the capacity to form 2 to 4 times more colonies in liquid medium than the controls, and to develop large tridimensional colonies in semisolid medium. The role of Scrapie in these changes is discussed.

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↗