SummaryDental germs of the upper incisors of six-days old rats were studied for the uptake of leucine-H3 by different layers of the enamel organ in correlation to the various stages of the development of enamel.The longitudinal section of the tooth germ was divided into 15 zones of about equal length in order to facilitate the description and interpretation of results. Autoradiographic images of the histologic preparations from rats sacrificed 30 minutes, 1 hour, 1 day and 3 days after the injection were made. The strongest reactions were observed in dental germs of rats sacrificed 1 hour, and particularly one day, after the leucine-H3 injection.The uptake of this compound by the enamel matrix increases progressively up to the young enamel and then decreases to the distal extremity; the greatest quantity of this labeled amino-acid was observed in the primary and young enamel. The reactions were present in the transitional enamel only along a thin band close to the dentine-enamel junction.In the enamel organ leucine-H3 incorporation was greatest in the three layers, the zones corresponding to primary and young enamel. In zones corresponding to transitional enamel, the inner epithelium showed a small quantity, and the stellate reticulum a blackening only in its superficial part, were the blood vessels reach the enamel organ.
Immunohistochemical expression of podoplanin (D2-40), lymphangiogenesis, and neoangiogenesis in tooth germ, ameloblastomas, and ameloblastic carcinomas