title: Fine structural observations of calcium storage in human dental pulp cells in primary culture.
abstract: Primary culture of explants of human dental pulp tissue allows the study of the cytophysiology and differentiation of the cultured cells over a two-week period. The distribution of calcium was found in two different experimental conditions : with and without a calcium loading, by mean of a lead technique checked by microprobe analysis. The existence of two cell populations was revealed. Intra-mitochondrial ring-like granules characterize type 1 cells when overloaded, while a strong calcium storage is detected in the rough endoplasmic reticulum, Golgi apparatus and mitochondrial (without any inner organization of the deposits) of the type 2 cells. Our results also show the presence of calcium on gap-junctions (revealed) by lanthanum method), and on the extracellular matrix (collagen fibres and complex carbohydrates). The ability of some mitochondria to store calcium (ring-like granules) suggests that the type 1 cells are fully differentiated in odontoblast-like cells and perhaps engaged in mineralization processes. The calcium binding sites, localized on the extracellular matrix may therefore be considered as the earliest foci of calcification.
mesh_terms: D002118:Calcium / Q000378:metabolism*; D002454:Cell Differentiation; D002478:Cells, Cultured; D003782:Dental Pulp / Q000166:cytology / Q000378:metabolism / Q000648:ultrastructure*; D006801:Humans; D008928:Mitochondria / Q000378:metabolism; D013194:Staining and Labeling; D014074:Tooth Calcification
chemical_list: D002118:Calcium