Early Stage Of Calcification Research Articles

Silicon: a possible factor in bone calcification.

Silicon, a relatively unknown trace element in nutritional research, has been uniquely localized in active calcification sites in young bone. Silicon increases directly with calcium at relatively low calcium concentrations and falls below the detection limit at compositions approaching hydroxyapatite. It is suggested that silicon is associated with calcium in an early stage of calcification.

Fine structure of early cartilage calcification

Cartilage at an early stage of calcification, as shown by an electron microscope study of costochondral junctions of 1-month-old guinea pigs, and of proximal tibial—distal femoral epiphyses of 3-day-old rats, is characterized by the formation of osmiophilic, PAS-reactive, roundish bodies, having amorphous structure and pericellular distribution. Calcification starts inside these bodies, which gradually become filled with crystallites. These form roundish clusters, which coalesce, surrounding collagenous fibrils, and the cartilage matrix becomes entirely calcified. Decalcification by means of EDTA, hydrochloric acid, or formic acid removes all the crystallites from the sections. However, if decalcification is performed with PTA, or if uranyl acetate and/or lead citrate staining follows decalcification with EDTA, hydrochloric acid or formic acid, an organic framework is revealed in the place of each apatite crystallite. This framework is partially extracted if the decalcification is carried out before embedding. It is suggested that the framework may nucleate calcium salts and that it is an intrinsic component of the crystallites.