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Biomedical subjects

H Magloire

Publications and source records attributed to H Magloire.

At least 73 records · Page 4Linked to original sources
PubMed1987

Supernatant from an activated human CD4+ T-cell clone modulates the proliferation and collagen synthesis of human dental pulp fibroblasts.

Several studies indicate a relationship between immunocompetent cells and fibroblast functions such as proliferation and collagen synthesis, which may be of importance in understanding the process of fibrosis. We demonstrate here the activity of supernatant from an activated human CD4+ proliferative T-cell clone (2F1) in stimulating the proliferation of human dental pulp fibroblasts, while inhibiting their soluble type I collagen secretion in either growing or confluent cultures. Taken together, our results indicate that T-cell derived lymphokines may be of importance in regulating normal dental pulp fibroblast functions.

Cell Division↗
PubMed1986

Type-I collagen production by human odontoblast-like cells in explants cultured on cyanoacrylate films. Electron-immunolocalization of fibronectin at cell/film interface.

Odontoblast-like cells derived from human tooth pulps were maintained in explant culture and grown either on glass coverslips only (used as control) or on glass coverslips coated with cyanoacrylate films. Ultrastructural and cyto-morphometric evidence showed that cells exposed to cyanoacrylate, in contrast to controls, display a significant decrease of rough endoplasmic reticulum and mitochondria. In addition, immunofluorescent staining and radioimmunoassays for type-I collagen suggested disturbances in production for the exposed cells. The use of anti-fibronectin antibodies with electron-microscopic immunoperoxidase-labelling demonstrated that the adherence of cells to cyanoacrylate can involve both adhesion plaques and fibronectin. These results therefore suggest that there were no apparent differences in the adhesion interaction of cells between glass and cyanoacrylate substrates.

Cell Adhesion↗
PubMed1986

Ultrastructure of multilayered cultures of human gingival epithelial cells: attachment to enamel surfaces in vitro.

Human gingival cells were collected using an enzymatic procedure and seeded on a feeder layer of irradiated mouse 3T3 fibroblasts. Epithelial cells generate stratified colonies ultimately forming an epithelium which was studied using electron microscopy. When this epithelium-like structure was dispased and transferred to enamel surfaces, the relationship between basal cells and enamel corresponded to half-desmosomes and a discontinuous extracellular matrix.

Adult↗
PubMed1985

Intercellular junctions in human tooth-pulp cells in culture in vitro revealed by freeze-fracture, lanthanum impregnation and filipin treatment.

Three kinds of intercellular junctions were detected between human dental pulp cells in explant culture with electron microscopy included filipin detection for cholesterol; desmosome-like junctions observed on ultrathin sections probably contribute to the cohesiveness between cells in culture. Gap junctions, responsible for intercellular communication, exhibited two morphologies on freeze-fracture replicas: a conventional arrangement of their intramembranous particles and a crystalline array corresponding to the formation stage of junctions. Primitive tight junctions were detected on freeze-fracture replicas but not on ultrathin sections. It is likely that they contribute to the cell-to-cell adhesion under culture conditions.

Cells, Cultured↗
PubMed1985

Early mouse molar root development: cellular changes and distribution of fibronectin, laminin and type-IV collagen.

We analysed epithelial-mesenchymal interactions that occur during the early stages of the formation of mouse molar roots using light and electron microscopy. Morphological changes observed in the cells of Hertwig's epithelial sheath, the pulp and the follicular mesenchyme are described. The Hertwig's epithelial cells lose their cuboidal form and become flattened, apparently intermixing with the cells of the follicular mesenchyme. At the light- and electron-microscope levels, immunoperoxidase techniques were used to localize fibronectin, laminin and type-IV collagen. These appear to be closely associated with cell differentiation and matrix deposition in developing tooth roots. In addition, at the ultrastructural level, intracellular immunoreactivity was detected. The rough endoplasmic reticulum and nuclear envelope of some cells of the periodontal ligament facing the acellular cementum exhibited specific reactivity with laminin and type-IV collagen. Moreover, these periodontal ligament cells express keratin, but not vimentin, filaments. Our results demonstrate that Hertwig's epithelial cells maintain their capacity to synthesize laminin and type-IV collagen, as well as to express keratin filaments, despite basement membrane fragmentation and the disorganization of Hertwig's epithelial sheath. Thus, some Hertwig's epithelial cells remain in the periodontal ligament intermixed with follicular mesenchyme cells.

Animals↗
PubMed1985

Influence of fixative on the fine structure of mouse odontoblasts: a study on undemineralized tissue.

The present report describes techniques of fixation and embedding suitable for studying the fine structure of odontoblasts without demineralization. The quality of the procedures employed was verified by comparing the ultrastructural preservation of the odontoblasts prepared by simple fixation and by the double-fixation method. Simple fixation by immersion in osmium tetroxide in vacuum preserves the longitudinal arrangement of the rough endoplasmic reticulum and Golgi apparatus, showing various vesicles which often contain filamentous threads of weak electron density aligned in parallel at repeating intervals typical of odontoblastic cells. The results obtained with this method are compared to previous descriptions of the ultrastructure of odontoblasts.

Animals↗
PubMed1984

Fibronectin in basement membrane of Hertwig's epithelial sheath. Light and electron immunohistochemical localization.

The distribution of fibronectin throughout the basement membrane of Hertwig's epithelial sheath was studied using specific antibodies with the immunoperoxidase technique in both light and electron microscopy. Our results demonstrate that, after collagenase digestion in situ, the basement membrane was strongly labelled by antifibronectin antibodies on the lamina lucida, the lamina densa and the lamina (pars) fibroreticularis which contained aperiodic fibrils of 5-10 nm in diameter.

Animals↗
PubMed1983

Light and electron immunoperoxidase localization of minor disulfide-bonded collagens in fetal calf epiphyseal cartilage.

New minor disulfide-bonded collagens were recently described in cartilaginous tissues. The localization of these molecules in epiphyseal proper and growth plate cartilage of fetal calf has been studied using light and electron immunoperoxidase microscopy. The labeling was restricted to the pericellular region of the chondrocytes with an increasing intensity form the superficial to the inner zone of the epiphysis. At the ultrastructural level, the fine-non striated fibrils of the pericellular matrix were stained, demonstrating their collagenous nature. These minor collagenous chains are thus new components of the chondrocyte "exoskeleton" in which other molecules (proteoglycans, chondronectin, fibronectin and type V collagen) have been previously demonstrated.

Animals↗
PubMed1983

Immunohistochemical localization of fibronectin-like protein on the cell surface of the oral flagelatte Trichomonas tenax.

A protein immunologically related to fibronectin was demonstrated on the oral flagellate Trichomonas tenax. Two strains of T. tenax were used, the first freshly taken from ulcerative gingivitis and the second maintained in culture for 2 years. Initial investigations were made by established immunofluorescence staining procedures. Cells of the protozoa gave a positive fluorescence with anti-fibronectin anti-serum, while the controls were negative. Subsequently, indirect immunostaining procedures for electron microscopy were performed using the peroxidase procedure. Peroxidase deposits were detected on the outer layer of the cell membrane. Particularly intense labelling was localized in the contact areas between bacteria and protozoa, and sometimes within the marginal lamina of the undulating membrane. This fibronectin-like protein could potentially play an important role in the adhesion of Trichomonas tenax to gingival cells, connective tissue and in the phagocytosis of bacteria. The attachment of protozoa to gingival substrates could be the first step in the breakdown of periodontal tissues.

Cell Membrane↗