[Crystallization of fibrils, chondroid and osseous mineralization in desmal osteogenesis and intervertebral disk]

Abstract

We reported on similar findings concerning the intercellular substances in the early desmal osteogenesis in cattle fetuses and rats and in the intervertebral disc of cats. In 0oth regions fibrils change their structure. In early desmal osteogenesis the bone fibrils are synthetized by osteoblasts, derived from mesenchymal cells. Later the fibrillar structure is lost and substituted by a homogenous substance. Chondroid starlike mineral deposits which are composed of needles appear in the vicinity of the cells. The chondral needles are longer and smaller than those in the bone. Finally the chondral needles are removed by mineraloclasts. During the next step frbrils reappear. They are accompanied by needles in their longitudinal axis. In adult cat the fibrils of intervertebral disc cross directly in bone. The fibrils of fibrocartilage are partly swollen and escorted by starlike mineral deposits. Between the bone fibrils partly amorphous mineral deposits are found generally needle-like along the fibrils. The nucleation of minerals takes place at random. The crystal growth is correlated to the structure and composition of organic intercellular substances and their morphological shape differs correspondingly, being chondroid in the fashion of stars, amorphsus and osseous when in contact and parallel to the fibrils.