A newly developed saw technique was developed to produce sections circa 10 microns or thicker from fresh bone or dentine and from plastic embedded undecalcified bone tissue with or without implant materials. The method comprises only one step because grinding or polishing to make the sections thinner is not necessary. The bone slices can be decalcified rapidly without using aggressive solvents and used for making ultrathin sections for electron microscopy. Sections of fresh dentine of 15 to 30 microns are transparent which makes it possible to study osteoclastic resorption in vitro. Sections, 10 microns thick, with an intact interface of bone and implant material can be observed for biocompatibility studies.

Skeletal tissues contain, apart from cells of the osteogenic and chondrogenic lineage, cells of hemopoietic origin, e.g., macrophages, osteoclasts, and their precursors. In the present study we examined the sensitivity for extracellular ATP4- of the above-mentioned cell types in freshly isolated, bone-derived cell populations and in explanted fetal metatarsal bones. Cells of hemopoietic origin reacted to the presence of ATP4- with an increased permeability for impermeant cytotoxic molecules, e.g., ethidium bromide (EB), thiocyanate (KSCN), and an increased non-ion selective membrane conductance. As a consequence, these cells could be killed by a short treatment with adenosine-5' triphosphate (ATP)+KSCN. On the other hand, cells of nonhemopoietic origin (e.g., osteoblasts, chondrocytes) were found to be insensitive to ATP4- in this respect. These cells survived the treatment without apparent damage to their alkaline phosphatase activities, osteogenic potentials, and osteoclast induction capacities. The elimination of the endogenous cells of hemopoietic origin from bone tissue or cell populations derived therefrom offers the possibility to study the properties and functions of osteogenic or chondrogenic cells without interference by the presence of cells of hemopoietic origin. It also allows the study of interactions between osteogenic cells and selected cell populations of hemopoietic origin in coculture experiments.

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