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Biomedical subjects

A Staubli

Publications and source records attributed to A Staubli.

18 recordsLinked to original sources
PubMed1989

Direct visualization of an IgM directed against a membrane antigen involved in both cell-matrix interactions and microfilament organization.

Dental mesenchymal cells were cultured in the presence of a monoclonal antibody. MC16A16, consisting of IgM and directed against a hydrophobic 165 kDa protein. Since the epitope recognized by MC16A16 was found to be at the outer cell surface, a direct visualization of IgM antibodies was used to localize the 165 kDa antigen by transmission electron microscopy. The present results demonstrate that the 165 kDa antigen is a membrane protein.

Actin Cytoskeleton↗
PubMed1989

Immunoperoxidase localization of fibronectin during odontoblast differentiation. An ultrastructural study.

Immunoperoxidase labeling of fibronectin in one-day-old mouse first lower molars allowed to visualize a striking redistribution of this glycoprotein during terminal cytodifferentiation of odontoblasts. The modifications involved both extracellular and cell surface localizations. The possible roles of these modifications in terminal differentiation of odontoblasts are discussed.

Animals↗
PubMed1988

Lipid detection by malachite green-aldehyde in the dental basement membrane in the rat incisor.

Developing rat incisors were treated with malachite green-aldehyde fixative solution (MGA), which retains and stains lipids. We observed positive staining occurring as dots in the basement membrane. Most of these dots (2-3.5 nm in diameter) were grouped in the lamina densa but some were also present in the lamina lucida and the lamina fibroreticularis. These data provide evidence for the existence of lipids in the dental basement membrane and suggest that they are distributed together with the various groups of proteins so far detected.

Aldehydes↗
PubMed1988

Effects of glycosaminoglycans on in vitro mouse dental cells.

Trypsin-dissociated dental papillae and enamel organs removed from the first lower molars of day-18 and day-19 mouse embryos were cultivated for 2 to 4 days on Millipore filters in DMEM supplemented with 15 per cent fetal calf serum and chondroitin sulphate and hyaluronic acid, individually or together. Three concentrations of glycosaminoglycans (GAGs) were also added to the media (01, 0.2, 0.4 mg/ml). Control cultures were made in the absence of GAGs, and additional experiments performed in which the presence of GAGs was associated with serum-free medium. Elongated and polarized odontoblasts showing synthetic activity were only observed in the presence of serum containing medium supplemented with 0.1 or 0.2 mg/ml of the GAGs. [3H]-thymidine autoradiography demonstrated that these cells were already post-mitotic at the onset of the culture. Polarized ameloblasts were never observed. These data provide evidence that GAGs are able to maintain the polarized state of cultured odontoblasts.

Ameloblasts↗
PubMed1988

Ultrastructural duality of extracellular fibrillar components of the odontoblast layer in the mouse molar.

The application of detergent solutions to dissociated molar dental papillae of mice permitted precise observation of the extracellular fibrillar material in the odontoblast layer and the predentine. Two types of fibrils were identified: cross-banded fibrils of variable diameter (25-200 nm) and aperiodic microfibrils of regular diameter (12.5 nm) and undetermined length. If the collagenic nature of the cross-banded fibrils is evident, the composition of the aperiodic microfibrils is probably different.

Animals↗
PubMed1986

Cell-matrix interactions: influence of noncollagenous proteins from dentin on cultured dental cells.

Matrix-mediated epitheliomesenchymal interactions control dental cytodifferentiations. Experiments were performed in order to study the effects of noncollagenous proteins extracted from dentin on cultured enamel organs and dental papillae. Seven noncollagenous protein fractions were prepared from rabbit incisor dentin and used as substrates to coat Millipore filters. Embryonic mouse tooth germs were dissociated and the isolated tissues were cultured for 4 days on these different substrates as well as on noncoated Millipore filters. When compared to control cultures, only two protein fractions affected the behaviour of epithelial cells. A slight elongation of the cell body and a preferential localization of the nuclei at the basal pole of the cells in contact with the filter was observed with protein fractions 5 and 6. When dental papillae were cultured on Millipore filters coated either with protein fraction 2 or fraction 6, the mesenchymal cells in contact with the filter elongated, polarized and demonstrated a high metabolic activity. Such modifications in the cell organization, implying changes in the cytoskeleton organization and, or, activity, never occurred spontaneously or in the presence of isolated collagens (I-V), laminin or fibronectin.

Amino Acids↗
PubMed1985

Acellular dental matrices promote functional differentiation of ameloblasts.

EDTA treatment of post-natal mouse molars made possible the isolation of cell-free dental matrices composed of basal lamina, predentin, dentin and enamel. Trypsin-isolated dental papillae and enamel organs from embryonic-mouse mandibular molars were combined with isolated matrices and cultured in vitro. In such recombinations, functional odontoblasts were never observed. On the other hand, competent preameloblasts in contact with the epithelial side of occlusal predentin overtly differentiated. Matrices treated with guanidine-EDTA or acetic acid were unable to promote the functional differentiation of ameloblasts. These data are discussed in terms of the epitheliomesenchymal interactions involved in odontogenesis.

Acetates↗
PubMed1982

Cytological response of the basal epithelial cell surface to the dental basement membrane.

Reassociations of trypsin-isolated dental or foot epithelia and trypsin or EDTA-isolated dental papillae were cultured for short and long time periods on a semi solid medium. After trypsin treatment the basement membrane (BM) is removed. After EDTA treatment an intact BM remains associated with the dental papilla. Cytochalasin B was added to a series of cultures. These experiments demonstrate the behaviour of the basal epithelial cell surface in the presence or absence of an intact dental basement membrane. In the presence of the dental basement membrane the epithelia restore a flat surface within one hour.

Animals↗
PubMed1981

Ruthenium rad staining and tannic acid fixation of dental basement membrane.

Ruthenium red staining and tannic acid fixation were used to analyse the fine structure of embryonic mouse dental basement membrane in intact first mandibular molars or in EDTA-isolated dental papillae. Preameloblasts are separated from extracellular matrix proper by a basal lamina that contains regularly arranged proteoglycan granules of about 10 nm in diameter. This distribution pattern is particularly evident in the inner and outer lamina rara of the basal lamina associated with EDTA-isolated dental papillae. The plasmalemma of preameloblasts demonstrates electron dense plaques on the inner leaflet. Ruthenium red positive granules (50 nm in diameter) coat nonstriated and striated fibrils of the matrix. Hyaluronidase treatment digested the ruthenium red positive granules. Tannic acid fixation allowed the demonstration of filaments within the lamina rara interna, connecting the lamina densa with plasmalemma of preameloblasts. These observations are discussed in the context of the terminal differentiation of odontoblasts.

Ameloblasts↗
PubMed1981

Cytochemical localization of adenylate-cyclase in embryonic mouse molars.

The cytochemical method of HOWELL and WHITFIELD (1972) and the revised cytochemical medium of KEMPEN et al. (1978) has been used to investigate the localization of adenylate-cyclase activity in 18, 19 and 20 day old first embryonic mandibular molars. Membrane associated precipitate granules were observed in preameloblasts and odontoblasts localized in the area where preodontoblasts become post-mitotic. Heat inactived teeth and the samples incubated in media without substrate were negative for membrane bound lead deposits. A correlation may exist between high adenylate-cyclase activity and the terminal differentiation of odontoblasts.

Adenylyl Cyclases↗
PubMed1979

[Anterior interbody fusion with neurological symptoms of a spondylolisthesis (author's transl)].

28 patients with spondylolisthesis who underwent anterior interbody fusion at the Orthopaedic Department of the University of Basle between 1968 and 1976, have been follow-up. In 90% satisfactory or good clinical results were achieved. In 82% the neurological symptoms - without laminectomy - were markedly improved or eliminated. According to the authors anterior interbody fusion (with reduction and enlargement of the intervetebral space) is indicated even when neurological symptoms are present.

Follow-Up Studies↗
PubMed1978

Basement membrane reconstitution and cytodifferentiation of odontoblasts in isochronal and heterochronal reassociations of enamel organs and pulps.

The restoration of the basement membrane and the terminal differentiation of odontoblasts were studied in iso- and heterochronal reassociations between dental mesenchyme and enamel organs. It was suggested that the cytodifferentiation of odontoblasts was triggered by the basement membrane secreted by the enamel organ of a specific stage.

Animals↗
PubMed1977

[Cellular relations during odontogenesis].

Epithelial-mesenchyme interactions during mouse molar tooth morphogenesis were observed by electron microscopy. The basal lamina was intact from day 10 to day 18. Aperiodic, later also periodic fibrils were deposited on the basal lamina. Ectomesenchymal cell processes were always in close relation with the basal lamina or with the fibrillar material. On day 19 some direct heterotypic cell contacts between odontoblasts and preameloblasts were observed. At all stages, especially the preodontoblasts but also preameloblasts, gave rise to aggregated vesicles, which were extruded in the epithelial-mesenchymal space.

Ameloblasts↗
PubMedDate not supplied

Epithelial-mesenchymal interactions: effects of a dental biomatrix on odontoblasts.

The functional differentiation of odontoblasts requires specific interactions between these cells and the extracellular matrix. To further analyze these phenomena we studied the effects of a "dental papillae biomatrix" on isolated dental papillae cultured in vitro. The dental papillae biomatrix was extracted from EDTA-dissociated day-18 mouse dental papillae by homogenization, NaCl and enzymatic treatments, and deposited on Millipore filters. This biomatrix was studied by means of transmission electron microscopy and indirect immunofluorescence: it contained collagen fibrils, type IV collagen, fibronectin and laminin; cellular residues were also observed. The dental papillae were isolated by trypsin treatment of homologous tooth germs and cultured on uncoated (control) and coated filters. As shown by histological and cytological data, odontoblast-like cells never differentiated in control cultures. In presence of biomatrix and serum, polarized functional cells were observed. The functional state of these cells was enhanced by the addition of ascorbic acid to the culture media. Study of the incorporation of 3H-proline in cultured dental papillae and in macromolecules secreted into the culture media corroborated the morphological findings.

Animals↗
PubMedDate not supplied

[In vivo study of the distribution, affinity for cartilage and metabolism of glycosaminoglycan polysulphate (GAGPS, Arteparon)].

37 patients suffering from osteoarthritis and 10 arthritic patients received intramuscular (i.m.), partly also intraarticular (i.ac.) injections of GAGPS; whereupon pharmacokinetics in serum, synovial fluid, urine, and cartilage were investigated. Cartilage was obtained during endoprosthetic hip surgery. The concentrations were determined by radiochemistry, partly after gel chromatography and electrophoresis respectively. Serum levels in patients with osteoarthritis after i.m. administration of 50 mg were 0.55 microgram/ml 3 hrs later, and 0.11 microgram/ml 24 hrs later. Patients with arthritis showed similar serum levels which were slightly higher after i.ac. injection, and which rose proportionally when the dosage was increased to 125 mg. With the arthritic patients, also the concentrations in the synovium were comparable, in the cases with osteoarthritis concentrations were slightly higher, which in both cases suggests that the synovial membrane is promptly penetrated. However, the concentrations in cartilage following a dosage of 50 mg within 24 hours rose as high as 1.45 micrograms/g which corresponds roughly to three times the serum level 3 hours after application. According to biochemical data, injections of 1 to 2 micrograms/ml should yield chondroprotective effects. Hitherto therapy has relied mainly on i.ac. injections; it may now be expanded by the i.m. route of administration. GAGPS was bound to serum proteins, in the synovia, however, it was found unbound. The main portion of the compound excreted via urine within 12 hrs (30 to 40 percent) was mainly unaltered; later, a partial degradation of the chain length and of the degree of sulfation was observed. Animal experiments on rats showed an increased affinity of GAGPS to inflamed tissues (Freund's adjuvant, carageenan edema).

Arthritis↗