Biomaterial Database

Ultrastructural and cytochemical studies of resorptive and digestive functions of secretory ameloblasts in kitten tooth germs. 1983

T Sasaki

Ultrastructural and cytochemical studies of kitten secretory ameloblasts were made in order to clarify their functions in the resorption and digestion of extracellular organic materials. The secretory ameloblast had triangular Tomes' processes whose profile was divided into type 1 and type 2 faces. Type 1 face was associated with tubular structures, coated pits, coated vesicles, and irregularly shaped vesicles presumably representing phagosomes. Freeze-fracture replicas clearly showed the presence of large, particle-rich depressions and small depressions on the cell membrane P face in the type 1 face of the Tomes' process. Exocytosis of secretory granules was seldom observed. In both thin sections and replicas, the type 2 face possessed cell membrane microinvaginations. From the supranuclear region to a zone near the Tomes' process, many dense bodies, multivesicular bodies, and vacuoles were present; and many of them showed intense acid phosphatase reactions. Reaction products of acid phosphatase were demonstrated in the Golgi apparatus, GERL, and the lateral cell membrane. These results suggest that kitten secretory ameloblasts resorb and digest extracellular organic materials.

UI	MeSH Term	Description	Entries
D002415	Cats	The domestic cat, Felis catus, of the carnivore family FELIDAE, comprising over 30 different breeds. The domestic cat is descended primarily from the wild cat of Africa and extreme southwestern Asia. Though probably present in towns in Palestine as long ago as 7000 years, actual domestication occurred in Egypt about 4000 years ago. (From Walker's Mammals of the World, 6th ed, p801)	Felis catus,Felis domesticus,Domestic Cats,Felis domestica,Felis sylvestris catus,Cat,Cat, Domestic,Cats, Domestic,Domestic Cat
D004063	Digestion	The process of breakdown of food for metabolism and use by the body.
D005614	Freeze Fracturing	Preparation for electron microscopy of minute replicas of exposed surfaces of the cell which have been ruptured in the frozen state. The specimen is frozen, then cleaved under high vacuum at the same temperature. The exposed surface is shadowed with carbon and platinum and coated with carbon to obtain a carbon replica.	Fracturing, Freeze,Fracturings, Freeze,Freeze Fracturings
D006651	Histocytochemistry	Study of intracellular distribution of chemicals, reaction sites, enzymes, etc., by means of staining reactions, radioactive isotope uptake, selective metal distribution in electron microscopy, or other methods.	Cytochemistry
D000042	Absorption	The physical or physiological processes by which substances, tissue, cells, etc. take up or take in other substances or energy.
D000135	Acid Phosphatase	An enzyme that catalyzes the conversion of an orthophosphoric monoester and water to an alcohol and orthophosphate. EC 3.1.3.2.	Acid beta-Glycerophosphatase,Acid beta Glycerophosphatase
D000565	Ameloblasts	Cylindrical epithelial cells in the innermost layer of the ENAMEL ORGAN. Their functions include contribution to the development of the dentinoenamel junction by the deposition of a layer of the matrix, thus producing the foundation for the prisms (the structural units of the DENTAL ENAMEL), and production of the matrix for the enamel prisms and interprismatic substance. (From Jablonski's Dictionary of Dentistry, 1992)	Ameloblast
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D014083	Tooth Germ	The collective tissues from which an entire tooth is formed, including the DENTAL SAC; ENAMEL ORGAN; and DENTAL PAPILLA. (From Jablonski, Dictionary of Dentistry, 1992)	Germ, Tooth,Germs, Tooth,Tooth Germs