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Biomedical subjects

C Chavrier

Publications and source records attributed to C Chavrier.

At least 19 recordsLinked to original sources
PubMed2000

A histological investigation on early tissue response to titanium implants in a rat intramedullary model.

Miniature grade 1 titanium screws were inserted in the tibias of 12 mature Wistar rats. Animals were sacrificed at 4, 7, and 21 days postimplantation. A combination of two morphological approaches was used to examine the tissue response to implants. One part of the prepared tissue specimens was routinely embedded in paraffin after a weak decalcification in EDTA. In this case, the implant was mechanically removed before embedding. The remainder of the specimens were embedded in polymethylmethacrylate resin, and ground sections were realized according to Donath's method. New bone formation occurred soon after implantation. Initially, on the fourth day, the presence of osteoid could be observed near the implant surface. On the seventh day, well-mineralized bone tissue was apposed directly on the implant surface. On the 21st day, the bone tissue became a highly organized lamellar bone.

Animals↗
PubMed1997

[Bone grafts from the chin in the treatment of thin alveolar crests].

Based on clinical experience, the minimum required alveolar ridge width must be of 5-6 mm in patient evaluation for the placement of endosseous dental implants. In comparison with other techniques, the use of autogenous mandibular chin grafts to enlarge thin alveolar ridges seems to be very efficient with a success rate of 88.57%. Advantages are: only one surgical field; minimal resorption after grafting; good predictability; minimum postoperative complications. The surgical technique is described step by step and a longitudinal study in 35 patients shows the high predictability of the method.

Alveolar Process↗
PubMed1994

Qualitative study of collagenous and noncollagenous glycoproteins of the human healthy keratinized mucosa surrounding implants.

The purpose of this study was to analyse the distribution of interstitial collagenous and noncollagenous glycoproteins of keratinized mucosa surrounding successful endosseous implants. Biopsies were incubated with highly purified antibodies against types I, III, IV collagen, laminin and fibronectin and routinely observed by immunofluorescence staining. Whereas no significative difference in the distribution of collagenous components was observed in comparison with healthy human gingiva, the collagen fibers of the connective tissue attachment ran parallel to the long axis of the implant. In 50% of the biopsies the gingival connective tissue underlying the junctional epithelium was rich in inflammatory cells and poor in collagenous components. However, the increased staining of type III collagen and the intense presence of fibronectin in this area reflect the very important remodeling ability of the local keratinized mucosa.

Collagen↗
PubMed1992

Targeted degradation of c-Fos, but not v-Fos, by a phosphorylation-dependent signal on c-Jun.

The proto-oncogene products c-Fos and c-Jun heterodimerize through their leucine zippers to form the AP-1 transcription factor. The transcriptional activity of the heterodimer is regulated by signal-dependent phosphorylation and dephosphorylation events. The stability of c-Fos was found to also be controlled by intracellular signal transduction. In transient expression and in vitro degradation experiments, the stability of c-Fos was decreased when the protein was dimerized with phosphorylated c-Jun. c-Jun protein isolated from phorbol ester-induced cells did not target c-Fos for degradation, which suggests that c-Fos is transiently stabilized after stimulation of cell growth. v-Fos protein, the retroviral counterpart of c-Fos, was not susceptible to degradation targeted by c-Jun.

Amino Acid Sequence↗
PubMed1992

Phosphorylation state and DNA-binding activity of c-Jun depend on the intracellular concentration of binding sites.

The DNA-binding activity of c-Jun expressed in eukaryotic cells was found to be markedly enhanced if the intracellular concentration of binding sites for this transcription factor was increased by cotransfection of specific plasmid DNA. Dephosphorylation experiments, phosphate mapping studies, and mutational analysis indicate that phosphorylation of a cluster of serine and threonine residues situated in close proximity to the DNA-binding domain is responsible for the observed adaptation of c-Jun activity to the intracellular concentration of accessible target sites.

Base Sequence↗
PubMed1990

The elastic system fibres in healthy human gingiva.

In human gingiva, the elastic system fibres, namely oxytalan, elaunin and elastic fibres, are distributed in the upper, medium and deep layers of gingival connective tissue, respectively. They are formed by a microfibrillar and an amorphous component characterized as elastin. In the gingival connective tissue fibroblastic cells are likely to be the main source of production of elastin in the extracellular matrix. Elastin is secreted as a soluble precursor (tropoelastin), which spontaneously forms insoluble aggregates of elastin. Elastin is then laid down at the surface of the microfibrillar component, which could serve as a site for deposition of elastin during elastogenesis, and subsequently be incorporated in an amorphous area to form elaunin and elastic fibres.

Actin Cytoskeleton↗
PubMed1990

[Elastic system fibers of healthy human gingiva].

The elastic system fibers, i.e. oxytalan, elaunin and elastic fibers have respectively a fibrillar structure (oxytalan fibers), an amorphous structure (elastic fibers), or a mixed structure (elaunin fibers). The morphological distribution of these fibers is characterized by the presence of oxytalan, elaunin and elastic fibers in the upper medium and deep layers of gingival connective tissue. If the amorphous component is made up of elastin the microfibrillar component consist of structural glycoproteins containing aminoacids different of those found in elastin. Elastin is synthesized by gingival fibroblasts in the form of a precursor, tropoelastin, then disposed at the surface of the microfibrillar component and incorporated in the amorphous component.

Contractile Proteins↗
PubMed1989

Immunohistochemical study of types I, III and IV collagen in diseased human gingiva of patients with rapidly progressive periodontitis: a light and electron microscopic study.

The distribution of type I, III and IV collagens and their ultrastructural organization have been studied in diseased gingival connective tissue of patients with rapidly progressive periodontitis. This disease is characterized by acute destruction of the gingival collagenous components. The use of an immunofluorescent procedure has shown that the diseased connective tissue was made up of both type I and III collagens but that type III collagen was less resistant to acute inflammation. Ultrastructural immunolabelling, using the peroxidase procedure has shown that the large, dense bundles of type I collagen of PI, the main pattern of organization of the gingival connective tissue offered a better resistance to acute destruction than PII, a loose pattern of organization mainly composed of type III collagen. Type IV collagen was exclusively located in degraded lamina densa of basement membrane.

Adult↗
PubMed1988

Distribution and organization of the elastic system fibres in healthy human gingiva. Ultrastructural and immunohistochemical study.

The ultrastructural distribution and organization of the elastic system fibres, i.e. oxytalan, elaunin and elastic fibres, were studied by transmission electron microscopy and by an immunohistochemical method for the detection of elastin in healthy human gingiva. The morphological distribution of these fibres was characterized by the presence of oxytalan, elaunin and elastic fibres, respectively, in the upper, medium, and deep layers of gingival connective tissue. Anti-elastin antibody reacted with microfibrils and amorphous material of the elastic system fibres throughout the gingival connective tissue. These findings were interpreted as indicating that the microfibrils were associated with small amounts of elastin at their surface.

Adult↗
PubMed1982

Distribution of type III collagen in the pulp parenchyma of the human developing tooth. Light and electron microscope immunotyping.

The distribution of collagen type III throughout the pulp tissue from human developing tooth was studied using specific antibodies, immuno-fluorescence as well as immuno-peroxidase labelling for electron microscopy. Our results indicate that type III and type I collagen are present in the pulp. The staining intensity seems to correlate with the relatively high proportions of type III collagen biochemically found in pulp. In addition, type III collagen and reticulin fibres are similarly distributed, except that the Von Korff fibres were never detected with anti-type III collagen antibodies. Correspondingly, at the ultrastructural level, type III collagen appears as fine, branched filaments or electron dense material distributed throughout the tissue and particularly in close association with the plasma membrane of pulp fibroblasts. In contrast, type I collagen appears as typical coarse cross banded fibres.

Adolescent↗
PubMed1981

Immunohistochemical localization of type I, III and IV collagen in healthy human gingiva.

The distribution of type I, III and IV collagen in the gingival connective matrix was studied by indirect immunofluorescent techniques on biopsies of healthy human attached gingiva. This connective matrix would seem to be made up of an intricate pattern of these 3 collagen types. Type I collagen is the main component of all the layers of the gingival corium while type III collagen is mostly found in the upper layers underlying the gingival epithelium and within the blood vessel walls. Type IV collagen is only associated with basement membranes, particularly of the gingiva, endothelial cells of capillaries, blood vessel walls and nerves.

Adult↗