[Surface bioactive ceramics (preliminary report)]. / Povrchove bioaktivní keramika (predbezná zpráva).

The Research and Development Institute of Industrial Glass in the town of Teplice (North Bohemia) has developed bioceramics (BAS-O) with presupposed surface activity manifested during its implantation in the macroorganism. The test was carried out by means of Macor inert ceramics produced by Corning Co. In total there were performed 8 implantations of surface active bioceramics and 7 implantations of inert ceramics in the tibiae and femurs of four dogs. After two months the experimental animals were sacrificed and the implants were examined. All eight prisms of BAS-O surface active ceramics were firmly connected with the bone and could be removed from bones only by force. On the contrary, the control inert ceramics could be removed from the bone by a pincette. The contact X-ray pictures showed an interface of surrounding tissue around inert ceramics and contrary to this, in case of surface bioceramics the bone trabeculea penetrated into the implants. The surrounding fibrous tissue around inert ceramics was proved in all cases by microscopic examination. In case of surface active bioceramics the fibrous intermedial layer was not proved even by electron microscopy.

The submicroscopic structure of a chondroblastic osteogenic sarcoma.

Two patients are reported with a chondroid form of osteosarcoma, whose structure was also analyzed submicroscopically. The clinical and radiologic picture and the rapid lethal progress of the disease indicated an osteosarcoma, while both histologic and electron-microscopic investigation suggested the prevalence of malignant chondroid. Progress in the treatment of osteosarcoma makes it essential for diagnostic, therapeutic and prognostic reasons to reintroduce subclassification of these tumors in an attempt to correlate their morphological picture with their biologic properties. According to our experience to date, it seems that the cartilaginous component in no way ameliorates the rapid malignant penetration of the osteosarcoma. It is essential to distinguish these tumors from the usually much less malignant chondrosarcomas and to place the chondroblastic osteogenic sarcoma among in spite of the clear predominance of the malignant chondroid, and thus also introduce highly radical and combined therapy.

The calcified-noncalcified cartilage interface: the tidemark.

Tidemark is an interface which may better be defined by biochemical methods than by morphology. It originates, by chondrocyte activity, between calcified and noncalcified cartilage layers of any kind, hyaline or fibrous, in areas exposed to either loading (joint) or pulling (insertion). In the articular cartilage it appears with skeletal maturation, in other localizations it is age-independent. It should be regarded as a special instance of a broader phenomenon of the calcification/mineralization front. Inside the joint cartilage its changes reflect the slow remodelling of the calcified layer and its inapparent shift towards the surface of the articular cartilage. In the marginal transitional zone of the joint, tidemark smoothly passes into the periosteum. Chondrocytes on both sides of the tidemark are positive for alkaline phosphatase and the positive reaction continuously goes on to the periosteum.