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Biomedical subjects

S Franc

Publications and source records attributed to S Franc.

23 records · Page 2Linked to original sources
PubMed1989

Immunohistochemical study of the biological fate of a subcutaneous bovine collagen implant in rat.

The biological fate of a bovine collagen implant (Zyderm Collagen Implant ZCI), injected subcutaneously into rats, was studied by the immunoperoxidase technique using specific antibodies against the bovine implant and against types I, III, IV, V collagens, fibronectin and elastin. The implant remained in the animals until the end of the experiment (90 days), with no visible modification, as demonstrated by immunoperoxidase labelling and scanning electron microscopy. A slight inflammatory reaction was visible around the implant 24 h after injection and within the implant 3 days after injection. Fibroblast invasion began 7 days after injection. The chronology of the deposition in the implant of the host (rat) extracellular matrix components was as follows: by 24 h after injection, fibronectin was observed throughout the implant; types I and V collagens appeared on the 7th day, and, in contrast to surrounding connective tissue, type V collagen labelling was obtained without acid pretreatment of the section. Types III and IV collagens were detected inside the implant only 30 days after injection. At the end of the experiment (90 days), there was abundant types I and IV collagens after fibroblast migration, and abundant type IV collagen demonstrating an important vascularization. No elastic fibres could be detected inside the implant but they appeared as a dense network around the implant in host connective tissue.

Animals↗
PubMed1984

A routine method for contrasting elastin at the ultrastructural level.

A reliable, simple, and inexpensive method for ultrastructural investigation of elastin is described. This method uses uranyl acetate dissolved in absolute methanol, followed by an optional lead citrate counterstain. The procedure was tested on a number of animal and human tissues that had been fixed and processed differently.

Animals↗
PubMed1979

[Genesis of connective matrix of Veretillum cynomorium Pall. (Cnidaria-Anthozoa). Ultrastructural and autoradiographic study (author's transl)].

Ultrastructural study of the tissues of Veretillum cynomorium shows the presence of two mesenchymatous cellular states in the mesoglea: the nongranular mesenchymatous cells and the granular mesenchymatous cells. These latter possess, besides their cytoplasmic granules, some homogeneous fibrous inclusions, very similar to the fibrous material of the mesoglea. Granules and homogeneous fibrous inclusions are also present in the cytoplasm of some ectodermic and endodermic cells. These morphological results lead us to consider that mesoglea and epithelia can be occupied by the same granular cell type. Besides this, the digestive endodermic cells are sometimes very rich in heterogeneous fibrous inclusions histochemically identified as phagosomes. An autoradiographic study indicates two possible pathways for the synthesis of the mesoglea. The first involves the endoderm which elaborates the mesoglea at a fast rate but in small amounts. The second is due to the granular cells (mesenchymatous and epithelial) which show a slow rate of synthesis leading to the formation of the homogeneous fibrous inclusions. The heterogeneous fibrous inclusions of the digestive endodermic cell support the hypothesis of the involvement of these cells in mesogleal degradation.

Animals↗
PubMed1978

Calcification of the collagenous axial skeleton of Veretillum cynomorium pall. (Cnidaria: Pennatulacea).

The axial skeletal rod of Veretillium cynomorium consists of a fibrillar collagenous matrix calcified with calcite. The present paper describes ultrastructural and crystallographic details of its organization and deposition. At the inferior end of the rod is a calcification gradient between the noncalcified tip and the rest of the axis. Initial mineral deposits, which are sometimes associated with cell debris, give rise to calcitic nodules which enlarge by the radical growth of several lobes. These nodules fuse and form the core of the axis. Subsequent increase in diameter of the rod involves the radial development of irregular columns of calcite which arise from the peripheral nodules. Mineral surfaces exhibit a distinctive microarchitecture which can be related to the predominantly c-axis parallel growth of the calcite. Particular attention is paid to the relationship between mineral and matrix. The collagen fibrils, embedded in the calcite but never impregnated with it, are not responsible for the initial nucleation of mineral. The crystallographic orientation of the calcite also appears to be independent of these fibrils.

Animals↗