Ultrastructural Study of Bone Formation on Synthetic Hydroxyapatite in Osteoblast Cultures

Collagenase isolated rat calvaria cells forming a mineralized matrix in vitro were cultured in the presence of synthetic hydroxyapatite. Interactions between bone cells and hydroxyapatite biomaterial were followed by transmission electron microscopy. The appearance of a granular, collagen free, electron-dense layer at the periphery of the material was noted initially. Progressively, an amorphous, granular material formed and extended between the hydroxyapatite aggregates. Osteoblastic cells then synthesized an osteoid matrix which mineralized on the first formed granular collagen free layer, following a classical pattern of calcification . Demineralization of ultrathin sections confirmed the presence of this interface between the material and bone tissue formed in vitro

Wrinkling and necking instabilities for tube hydroforming

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Collagen expression during teratocarcinoma cell line-induced endochondral bone tumor.

International audienceCollagen immunotyping by indirect immunofluorescence was performed in order to investigate the sequential development of bone formation. Osseous tumors were obtained after subcutaneous injection of 3/A/1D-1 teratocarcinoma cell line into 129/Sv mice (Nicolas et al., 1980). Frozen sections of developing tumors were incubated with specific antibodies directed against Types I, II, III, IV, and IX collagens. On Day 9, the expression of Type I and Type III collagens was correlated with the proliferation of mesenchymal cells. From Day 10, chondrogenesis was characterized by the occurrence of cartilaginous collagens, Types II and IX, in the cartilage matrix. Type IV collagen was also detected in focal areas and revealed vascular invasion of the tumor. On Day 13, osteogenesis was demonstrated by the presence of Type I collagen in the bone matrix coating the surfaces. Immunolocalization of Type III collagen on the hemopoietic elements corresponded with the bone remodeling. The sequential transitions of collagen types confirm the development of an endochondral bone tumor. These results suggest that 3/A/1D-1 teratocarcinoma cell line constitutes a valuable system for in vitro study of endochondral bone formation and cell differentiation.Collagen immunotyping by indirect immunofluorescence was performed in order to investigate the sequential development of bone formation. Osseous tumors were obtained after subcutaneous injection of 3/A/1D-1 teratocarcinoma cell line into 129/Sv mice (Nicolas et al., 1980). Frozen sections of developing tumors were incubated with specific antibodies directed against Types I, II, III, IV, and IX collagens. On Day 9, the expression of Type I and Type III collagens was correlated with the proliferation of mesenchymal cells. From Day 10, chondrogenesis was characterized by the occurrence of cartilaginous collagens, Types II and IX, in the cartilage matrix. Type IV collagen was also detected in focal areas and revealed vascular invasion of the tumor. On Day 13, osteogenesis was demonstrated by the presence of Type I collagen in the bone matrix coating the surfaces. Immunolocalization of Type III collagen on the hemopoietic elements corresponded with the bone remodeling. The sequential transitions of collagen types confirm the development of an endochondral bone tumor. These results suggest that 3/A/1D-1 teratocarcinoma cell line constitutes a valuable system for in vitro study of endochondral bone formation and cell differentiation

Comment ameliorer la performance de l'agro-alimentaire francais a l'export ? Une comparaison France, Pays-Bas, Danemark dans les secteurs du porc et du fromage

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