The effect of fluoride on the resorption of dentine by osteoclasts in vitro.

Osteoclasts were isolated mechanically from bones of prehatch chicks and cultured on dentine for 24 or 39 h in medium without or with added sodium fluoride at concentrations of 0.15, 1, 15, or 30 mg/liter. Fixed and toluidine blue-stained specimens were examined by light microscopy and osteoclasts were counted, all cells were removed and resorption pits were counted.

Human cranial bone structure and the healing of cranial bone grafts: a study using backscattered electron imaging and confocal microscopy.

This study explored the microstructure of human cranial bone at different ages, and the survival, remodelling and modelling of cranial bone grafts. A combination of reflection and fluorescence confocal optical microscopy and scanning electron microscopy in the backscattered electron imaging mode was employed to examine highly polished block faces of plastic-embedded bone fragments as harvested for grafting, or recovered after a period in situ as a graft. The methods enabled remarkably detailed information on bone content, maturation and turnover to be gleaned from tiny scraps of bone.

SEM study of surface alterations of bioactive glasses and glass--ceramics in a bony implantation bed.

Back scattered electron (BSE) images of glasses and glass-ceramics with different degrees of bone-bonding behaviour have been investigated. After the implantation of probes in the femur of rats changes of the surface material, induced by leaching and corrosion (material response) and of the tissue in the drill hole (host response), were studied. The results demonstrate advantages of using BSE images and give further information for understanding the sequential changes in the implant material which occur mainly in bone-bonding materials.

The effects of inhibitors of cysteine-proteinases and collagenase on the resorptive activity of isolated osteoclasts.

The effects of specific inhibitors of cysteine-proteinases ((Z-Phe-Ala-CHN2: benzyloxycarbonyl-phenyl-alanyl alanyl diazomethane and E-64: trans-epoxy-succinyl-L-leucylamido(4-guanidino)-butane) and collagenase and collagenase ((Cl-1: N-(3-N-benzyloxycarbonyl amino-1-R-carboxypropyl)-L-leucyl-O-methyl-L-tyrosine N-methylamide) have been tested on the osteoclastic resorption of dentine. Chick osteoclasts were cultured in the presence or absence of 12.5 microM Z-Phe-Ala-CHN2, 40 or 60 microM E-64, or 40 or 100 microM Cl-1 for 1 or 2 days.

Variation in the sizes of resorption lacunae made in vitro.

The assessment of in vitro osteoclastic activity has, until recently, been dependent on the analysis of organ culture experiments. We have developed a single cell resorption assay so that the resorptive function of individual osteoclasts could be studied. This paper examines the biological variation in the sizes of resorption lacunae produced by bone cell cultures derived from neonate rats and rabbits, and prehatch or hatchling chicks.

Scanning electron microscopy in bone pathology: review of methods, potential and applications.

This article reviews the applications of SEM methods to human bone pathologies referring to studies made at UCL. We consider the methods which may be most suitable; these prove to be not "routine" in the context of most bio-medical applications of SEM. Valuable information can be obtained from a bone sample if its edges are ground flat, before making either a matrix surface preparation by washing away all the cells or a mineralizing front preparation, by also dissolving the osteoid-for which hydrogen peroxide is recommended to produce a robust specimen.

Morphological correlations with dimensional change during SEM specimen preparation.

We have previously reported details of the dimensional changes taking place during the processing of soft tissue specimens for scanning electron microscopy. Mouse embryo limbs were used for many of these measurements and the present paper deals with the associated morphological findings. Effects of fixation, dehydration and drying are considered.

Treatment with lithium salts reduces ethanol dehydration shrinkage of glutaraldehyde fixed tissue.

Changes in the area of glutaraldehyde fixed 15 day p.c. mouse embryo limbs were recorded using a Quantimet 720 image analysing computer attached to a light microscope: during a period of treatment with an isotonic salt solution (mostly halides of the alkali or alkaline earth metals); a subsequent wash with distilled water; and dehydration through a 30, 50, 70, 80, 90, and 100% ethanol series.

A study of digit fusion in the mouse embryo.

During the embryonic development of the mouse limb separation of the digit is followed by their union. This is a true, though temporary, epithelial fusion, a fused layer of epidermal cells remaining intact until separation takes place after birth. The periderm cells in the line of fusion are displaced to the dorsal or ventral surface of the foot.