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Biomedical subjects

S J Coleman

Publications and source records attributed to S J Coleman.

9 recordsLinked to original sources
PubMed1980

Osteoid resorption by mononuclear cells in vitro.

For the first time, mononuclear cell-mediated ingestion of osteoid in cultures of long bones of fetal rats is described and characterized. The mononuclear cells, located at sites of osteoid deposition, ingest collagen fibrils and clumps of mineral crystals which are segregated within cytoplasmic vacuoles or multivesicular bodies. The ingestion of osteoid continues in cultures treated with agents that normally inhibit osteoclastic bone resorption. Morphologically, the osteoid-containing cells are characterized by a moderate number of mitochondria and short-stranded rough endoplasmic reticulum, a modest Golgi apparatus and variable numbers of vesicles, vacuoles, and multivesicular bodies. The morphologic appearance of the mononuclear cell is consistent with that of a macrophage.

Animals↗
PubMed1980

Effects of prostaglandin E2 on macrophages and osteoclasts in cultured fetal long bones.

Bone cultures exposed to prostaglandin E2 (PGE2) and revealed an increase in 45Ca release from bone to medium and an increase in osteoclast number compared to control bones. In addition, PGE2-treated osteoclasts contained a more extensive ruffled border region than control osteoclasts. These data suggest that PGE2 activates existing osteoclasts and causes proliferation and differentiation of osteoclast precursor cells. The existence of macrophages in resorbing fetal bone explants was documented. These macrophages contain numerous phagolysosomes and lipid vacuoles and are often located adjacent ot osteoclasts or closely apposed to calcified tissue surfaces. PGE2 caused an early increase in the number of macrophages. It is postulated that fetal bone macrophages are primarily engaged in phagocytosis and digestion of cellular debris, but also play a role in the process of bone resorption.

Animals↗
PubMed1980

Fine structure of fetal rat calvarium; provisional identification of preosteoclasts.

This is a study of the fine structure of cells of the 20-day fetal rat calvarium. Special attention is given to identifying and characterizing preosteoclasts. These cells are relatively common and located largely, but not exclusively, at the endocranial bone surface. The preosteoclasts are characterized by abundant mitochondria, an incomplete perinuclear Golgi apparatus, and variable-shaped dense granules. The dense granules are unique in appearance in that they contain an internal dense matrix surrounded by a clear halo. Most granules are circular in shape but some are elongate or tubular in form. Granules with identical appearance are observed in osteoclasts. The preosteoclasts are mononucleate, or occasionally binucleate. It is suggested that because preosteoclasts are morphologically distinctive dna relatively abundant, it should be feasible to separate these cells from a heterogeneous cell isolate.

Animals↗
PubMed1980

Data processing in pathology laboratories: the extension of the Phoenix system into haematology.

A computer data-processing system in the chemical pathology laboratories of the Royal Postgraduate Medical School at Hammersmith Hospital was described recently. This has now been extended to include the haematology laboratory. In the main, the original 'Phoenix' programs were adaptable to the new subject, but two major new programs were required, one to deal with automated blood counting by the Coulter S and one to accept film examination results on-line. The programs and procedures have been thoroughly tested and in routine use since 1977. The results have fully justified their introduction.

Computers↗
PubMed1979

An ultrastructural study of macrophage-mediated resorption of calcified tissue.

Ultrastructural observations on macrophage-mediated resorption of calcified tissue of killed fetal long bones are described and correlated with increased 45Ca release into the medium. Macrophages disrupt calcified tissue extracellularly and appear to engulf large fragments of mineralized matrix. Ruffled borders, which are common features of osteoclasts at sites of resorption of bone, do not develop in macrophages. However, clear zones are seen in macrophages as well as osteoclasts. These findings provide additional evidence for non-osteoclast-mediated resorption of calcified tissue.

Animals↗