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Biomedical subjects

B Delpech

Publications and source records attributed to B Delpech.

At least 91 records · Page 5Linked to original sources
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

Growth and differentiation of the gubernaculum testis during testicular descent in the pig: changes in the extracellular matrix, DNA content, and hyaluronidase, beta-glucuronidase, and beta-N-acetylglucosaminidase activities.

The gubernaculum testis is a loose connective tissue organ that plays an essential mechanical role in testicular descent. In the pig, the first phase of descent (transabdominal migration) is brought about by growth of the gubernaculum through the inguinal canal into the scrotum and simultaneous somatic growth of the fetus. During the second phase the gubernaculum condenses, thus allowing the testis to descend into the scrotum. The nature of gubernaculum development (growth and differentiation) was investigated with respect to cell proliferation, extracellular matrix (ECM) composition, and acid hydrolases. Deoxyribonucleic acid (DNA) was used as a measure of cell number and hydroxyproline (HYP) was an estimate of interstitial collagen. The first phase of gubernaculum development was characterized by rapid cell proliferation and concomitant synthesis of sulphated glycosaminoglycans (S-GAG), hyaluronic acid (HA) and collagen. During the second phase cell proliferation ceased and DNA concentration increased. The amount of S-GAG remained closely related to the amount of DNA while HYP increased further. However, HA decreased during the second phase and thus HA metabolism seems to play a crucial role in biphasic development of the gubernaculum. The activities of the enzymes that are needed for biodegradation of HA (hyaluronidase, beta-glucuronidase and beta-N-acetylglucosaminidase) were measured in gubernaculum homogenate from animals during the first and second phase of testicular descent. These enzymes were detectable in gubernaculum and rose during the second phase of testicular descent. It was concluded that a very distinct dichotomy in the nature of gubernaculum development during the first and second phase could be discerned with respect to cell proliferation rate and ECM synthesis and degradation. These observations provide useful tools for future in vivo and in vitro investigations into the process and regulation of testicular descent.

Acetylglucosaminidase↗
PubMed1988

Hyaluronectin: detection with monoclonal antibodies in human tumors.

Two monoclonal IgG1 antibodies (MAbs) were raised against human brain hyaluronectin (HN) and used to characterize tumor HN. They were screened using an enzyme immunological technique (ELISA) combined with the HN property of specific binding to hyaluronic acid. They were shown to detect two different epitopes (HN1 and HN2) in human normal brain as well as in most tumors. Both HN1 and HN2 epitopes were found associated with mesenchymal benign or neoplastic proliferations (e.g. connective areas of fibroadenomas, extracellular matrix of fibrosarcomas) and with reactive connective tissue (e.g. stroma reaction of carcinomas, ground substance of gliomas). The results corresponded with those previously obtained with polyclonal rabbit antibodies and confirmed that HN is a constant marker of desmoplasia. Thus anti-HN MAbs recognize an antigen that is associated with tumor development and will be suitable for targeting.

Antibodies, Monoclonal↗
PubMed1988

Serum hyaluronate in rheumatoid arthritis: study by affino-immunoenzymatic assay.

Serum level of hyaluronate (HA) was assayed by an affino-immunoenzymatic method using hyaluronectin, in 25 patients with rheumatoid arthritis (RA), 24 patients with ankylosing spondylitis (AS) and 103 controls. The mean serum HA level was significantly higher (p less than 0.001) in RA (171 +/- 39 micrograms/l) than in controls (22.4 +/- 1.6 micrograms/l) and AS patients (30.3 +/- 3.0 micrograms/l). The mean HA level in RA on corticosteroids (98.2 +/- 25.9 micrograms/l) was significantly lower (p less than 0.05) than that of RA without steroids (220.1 +/- 60.5 micrograms/l). The serum HA levels were not correlated with clinical or serological indicators of inflammatory activity. This increase in serum HA probably reflected an excessive production by rheumatoid synovium and not a lowered catabolism, all patients having normal hepatic function. The origin of the increased synthesis is still unknown. These results suggest that serum hyaluronate is not a universal indicator of inflammation but is perhaps a characteristic of RA.

Adolescent↗
PubMed1987

An indirect enzymoimmunological assay for hyaluronidase.

The use of a hyaluronic acid-binding proteoglycan (hyaluronectin) as a probe for the detection of hyaluronic acid has facilitated the development of an indirect enzymo-immunological assay for hyaluronidase. Plastic microtest ELISA plates were coated with hyaluronic acid. Incubation with hyaluronidase led to the destruction of insolubilized hyaluronic acid in proportion to the hyaluronidase concentration of samples. Residual hyaluronic acid was assayed by its capacity to bind immune complexes made up of hyaluronectin supplemented with alkaline phosphatase-conjugated anti-hyaluronectin antibodies. The technique was very sensitive and permitted the detection of as little as 10(-10) NFU of bovine testicular hyaluronidase. Hyaluronidase was detected by this technique in human sera, bee venom and culture medium of human hepatoma cell lines.

Antigen-Antibody Complex↗
PubMed1987

Serum hyaluronate in malignant pleural mesothelioma.

The diagnostic value of hyaluronate concentration in effusions of malignant mesothelioma has been extensively reported but no information is available about serum hyaluronate in patients with this cancer. Using a new enzymoimmunologic assay based on hyaluronate-hyaluronectin interaction, serum levels of hyaluronate were measured in 16 patients with malignant pleural mesothelioma, 50 patients with other pleural effusions, and 94 healthy blood donors. The mean serum hyaluronate level in patients with mesothelioma (mean, 750 micrograms/l; range, 29 to 5833 micrograms/l) was significantly higher than in patients with other pleural effusions (mean, 56 micrograms/l; range, 4 to 137 micrograms/l) and than in blood donors (mean, 24 micrograms/l; range, 0 to 94 micrograms/l). Comparison of serum hyaluronate values observed in mesotheliomas with the clinical course of the disease suggests that serum hyaluronate might increase only at an advanced stage of the cancer. Therefore, serum hyaluronate determination has probably no clinical value for early detection of malignant mesothelioma, but might be useful to evaluate the clinical course of this malignancy.

Adult↗
PubMed1986

Specific monoclonal antibodies to glial fibrillary acidic protein (GFAP).

Anti-glial fibrillary acidic protein (GFAP) monoclonal antibody has been obtained by fusing SP2/O myeloma cells with splenic cells from mice immunized with human GFAP. It belongs to the IgG1 class and it recognizes an epitope on GFAP which is shared by each fragment of the protein. Immunohistological studies show that the epitope characterized is absolutely specific for GFAP.

Animals↗
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↗
PubMed1986

[Characterization of lysosomal-type hyaluronidase in the culture medium of 2 cell lines derived from human hepatomas].

A sensitive assay for hyaluronidase was developed using as a substrate, hyaluronic acid insolubilized on polystyrene microtest plates. Hyaluronic acid was measured exploiting the fact that it can bind immune complexes made up with hyaluronectin and alkaline phosphatase-conjugated anti-hyaluronectin antibodies. Hyaluronidase was detected in both cell line culture media. Optimum pH was between 3.25 and 3.75. Sodium chloride dependence was absolute, and the optimum concentration of sodium chloride was between 0.2 and 0.3 M. The activity was not affected by dialysis, and was suppressed by a 5 minute heating at 50 degrees C or by protease treatment. The molecular weight was 68 K as determined by gel permeation chromatography. The results are close to those reported for human lysosomal hyaluronidase.

Carcinoma, Hepatocellular↗
PubMed1986

[Spontaneous bone marrow micrometastasis of a cerebral glioma. Immunohistochemical diagnosis in a biopsy sample and review of the literature].

A 55 year-old woman was admitted to hospital in January 1981 with transient expressive dysphasia. Past personal history was unremarkable except for a six-month history of renal colic and thrombophlebitis in the veins of the right leg. Computed tomographic scan of the head and carotid angiogram revealed a left calcified temporoparietal tumor. Because of pulmonary embolism it was decided to refute a cerebral biopsy. The patient also declined radiotherapy. In May 1983, a thorough workup revealed an incomplete fracture of the first lumbar vertebra and a diffuse demineralization of the rachis and pelvis. Four weeks later she developed temporal epilepsy and pulmonary embolism. A whole brain irradiation (60 Gy) was performed in August 1983. The patient's condition remained clinically stable until December 1984 when she was readmitted to hospital with a severe weight loss, diffuse osseous pain and pancytopenia. A bone marrow biopsy from the iliac crest showed a diffuse tumor involvement. Peroxidase-antiperoxidase staining using monoclonal antiserum to glial fibrillary acidic protein was strongly positive in numerous tumors cells. The pathological diagnosis was bone marrow metastasis by glioma. She died in March 1985, 4 years and 3 months after the first admission to hospital. Autopsy was not performed. A literature search reveals only 9 cases of extraneural spreading of astrocytomas and glioblastomas in the absence of previous craniotomy with post-mortem examination. The authors also comment on the clinical, pathological and histogenic aspects of extraneural metastasis of gliomas.

Bone Marrow Diseases↗
PubMed1985

Immunoenzymoassay of the hyaluronic acid-hyaluronectin interaction: application to the detection of hyaluronic acid in serum of normal subjects and cancer patients.

The binding of a hyaluronic acid-binding glycoprotein, hyaluronectin (HN), isolated from human brain, to hyaluronic acid (HA) was investigated with the enzyme-linked immunosorbent assay technique using plastic microtest plates coated with a 50 mg/liter solution of HA in 0.1 M bicarbonate. Optimum conditions for HN binding to HA were in 0.2 M NaCl buffered with 0.1 M sodium phosphate at pH 7. An assay for HA in solution was set up exploiting the fact that HN binding could be inhibited by soluble HA. HA was preincubated for 1 h in a test tube with a 30-ng/ml HN solution (v/v) in the buffer containing 0.1% bovine serum albumin. Incubation on HA-coated microtest plate lasted 4 h and maximum sensitivity was achieved when incubation was carried out at 4 degrees C. HN bound to the plate was revealed by means of alkaline phosphatase-conjugated anti-HN antibodies. The test was used to measure HA inhibitory activity after depolymerization by ferrous ions. No difference was found between inhibitory activity or smaller fragments and that of high-molecular-weight HA. The assay was applied to determination of HA in sera. Specificity was demonstrated by Streptomyces hyaluronidase digestion of reactive material in sera. Other glycosaminoglycans did not interfere with the assay. Recovery of HA was good and intra- and interassay variation coefficients were 6 +/- 2.2 and 12%. In 103 blood donor sera, HA was found at 22.4 +/- 16.7 micrograms/liter. HA was elevated in most of the cancer patient sera tested.

Adsorption↗
PubMed1985

Interaction of hyaluronectin with hyaluronic acid oligosaccharides.

Hyaluronic acid was digested by bovine testicular hyaluronidase, and oligomers were fractionated by gel permeation using AcA 202 Ultrogel, an acrylamide-agarose matrix. Oligosaccharides composed of from two to six disaccharide repeating units were isolated. Two nonasaccharides were prepared by enzymatic or chemical modification of the decasaccharide. Oligosaccharides were compared by a competitive inhibition in the enzyme-linked immunosorbent assay for their ability to inhibit the interaction of hyaluronectin (a hyaluronic acid-binding brain glycoprotein) with hyaluronic acid. Among these oligosaccharides, decasaccharides were the smallest fragments that strongly inhibited the interaction. Octasaccharides inhibited with 700-fold lower affinity than decasaccharides. Dodecasaccharides had the same effect as decasaccharides. Nonasaccharides obtained by beta-glucuronidase splitting of decasaccharides inhibited the interaction more than nonasaccharides prepared by an alkaline treatment.

Animals↗
PubMed1985

Expression of hyaluronectin by C-6 glial cells at high density.

Hyaluronectin, a brain glycoprotein that has been localized to the nodes of Ranvier in vivo and to oligodendrocytes in primary cultures of neonatal rat brain cells, was shown by using an unlabeled immunoperoxidase method to be present in C-6 glial cells grown to high density. The density-dependent expression of this glycoprotein is in accordance with the known properties of the glial stem cells, i.e., induction of differentiated properties such as 2',3'-cyclic nucleotide-3'-phosphohydrolase, glutamine synthetase, S-100 protein, and glial fibrillary acidic protein.

Animals↗
PubMed1985

[Formation of mixed spheroids by a coculture of human cancerous and fibroblast cells].

The coculture of fibroblasts with cancerous cells under the conditions which lead to spheroid formation, allowed the obtention of spheroids composed of a fibroblastic core surrounded by cancerous cells. The fibroblast core was labelled by hyaluronic acid and hyaluronectin. Hyaluronic acid concentration was also measured by enzymoimmunological assay in culture medium where it was found to accumulate during spheroid growth. The composite spheroid technique is a good model system for analysis of cancer cells-fibroblasts interaction in vitro.

Carrier Proteins↗
PubMed1985

[Xanthoastrocytoma inf young subjects. Review of the literature apropos of 2 cases with discordant courses].

Two cases of pleomorphic xanthoastrocytoma (P X A) of young subjects (Kepes et al., 1979) are reported. Case 1 arose in 15-year-old boy admitted to the hospital with the complaint of severe headaches associated with nausea and vomiting of 1 month's duration. Computed tomographic scans showed a large well-defined low density area in the left temporo-parietal region of which an anterior portion was enhanced by contrast medium. Craniotomy revealed a large superficial and cystic tumor with a mural nodule. Histological and immunohistochemical features were those of a P X A confirmed by an electron microscopic study. No radiotherapy was given. The patient made a complete recovery, and 32 months later was asymptomatic. Case 2, a 17-year-old boy was admitted to the hospital in 1977. He presented with seizures that started 18 months prior to surgery. Carotid and humeral angiograms and air studies indicated the presence of a right, internal temporal mass with herniation. The craniotomy revealed a firm superficial tumor with an infratentorial, extraparenchymal extension. The histological diagnosis was giant cell glioblastoma or gliosarcoma. The patient received post-operative radiation of 5.500 rads and chemotherapy (CCNU and VM 26). He died on the 7th post-operative month. In this 2nd case, the diagnosis of P X A was made retrospectively based upon histological and immunohistochemical observations similar to case 1. We are aware of 24 P X A in the literature. In their clinical and histological features these neoplasms resemble closely each other. P X A are superficial, supratentorial astrocytomas occurring in youngs subjects (ages 3 to 32). Their typical microscopic structure include a marked cellular pleomorphism with bizarre giant cells, some mitotic figures and no necrosis. Many cells contain lipid and hyalin droplets in their cytoplasm. Characteristically, the tumoral stroma contain a very rich reticulin fiber network. Immunoperoxidase technique reveal glial fibrillary acidic protein in the tumor cells. Electron microscopic studies demonstrate abundant intracytoplasmic glial filaments. Individual cells or group of cells are surrounded by a prominent basal lamina. Some hemidesmosomes or primitive attachments are seen at the margins of the tumor cells. The biological behaviour of PXA with or without radiotherapy is relatively favorable. Long survival times (up to 25 years) are reported but in 5 cases, P X A follow a less favorable course with malignant transformation and death. Morphologic and immunohistochemical studies support the subpial astrocytic origin of P X A.

Adolescent↗