caa a22 4500 46908233X CHVBK 20180323132954.0 cr unu---uuuuu 170328e19920101xx s 000 0 eng 10.1007/BF00318693 doi (NATIONALLICENCE)springer-10.1007/BF00318693 Zimmermann Bernd Institut für Anatomie der Freien Universität, Königin-Luise-Strasse 15, W-1000, Berlin 33, Federal Republic of Germany aut Degeneration of osteoblasts involved in intramembranous ossification of fetal rat calvaria [Elektronische Daten] [Bernd Zimmermann] Summary: Ossification of calvariae from day-21 rat fetuses was reinvestigated by electron microscopy using different fixation techniques (glutaraldehyde/OsO4, tannic acid, ruthenium red, K-pyroantimonate). An osteoid layer with scattered mineral deposits was found at the mineralization front. Directly beyond this layer, a sheet of one to two layers of necrotic and degenerating osteoblasts was present. Above this sheet, normal and healthy cells were seen, formed by six to eight layers of flattened cells, embedded in a collagenous matrix. The osteoblasts on the less mineralizing opposite side of the calcified cavariae and the osteocytes embedded in the calcified calvariae appeared healthy. Closer inspection of the necrotic zone revealed apatite crystal in vesicles which most probably originated from mitochondria of the degenerated cells. Large K-pyroantimonate deposits were found throughout the osteoid and the necrotic zone, whereas only small granules were scattered in the cytoplasm and at the plasma membrane of the healthy cells directly adjacent to the necrotic zone. A concept of intramembranous mineralization is outlined, according to which osteoblasts store enormous amounts of calcium, which are liberated by physiological cell death in the vicinity of the mineralizing front. Springer-Verlag, 1992 Osteoblasts nationallicence Desmal mineralization nationallicence Calvaria nationallicence Cell necrosis nationallicence Ossification nationallicence Mitochondria nationallicence Rat (Wistar) nationallicence Cell and Tissue Research Springer-Verlag 267/1(1992-01-01), 75-84 0302-766X 267:1<75 1992 267 441 https://doi.org/10.1007/BF00318693 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00318693 text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- Zimmermann Bernd Institut für Anatomie der Freien Universität, Königin-Luise-Strasse 15, W-1000, Berlin 33, Federal Republic of Germany aut NATIONALLICENCE 773 0- Cell and Tissue Research Springer-Verlag 267/1(1992-01-01), 75-84 0302-766X 267:1<75 1992 267 441 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer