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Biology

1989

Bone

Articles 1 - 4 of 4

Full-Text Articles in Life Sciences

Ultrastructural Features Of Osteoclasts In Situ, L. De Saint-Georges, S. C. Miller, B. M. Bowman., W. S. S. Jee Dec 1989

Ultrastructural Features Of Osteoclasts In Situ, L. De Saint-Georges, S. C. Miller, B. M. Bowman., W. S. S. Jee

Scanning Microscopy

The morphology of in situ osteoclasts on endocortical surfaces of the femoral midshaft was examined by scanning electron microscopy. Mice were perfusion fixed and bone marrow plugs were flushed out of femoral diaphyseal cylinders. The bones were split longitudinally and the endocortical surfaces examined. This method left on the bone surface most of the endosteal cells in their natural, in situ shape and position. Most of the bone surface was lined by contiguous bone lining cells covering resting bone surfaces, making a clear physical barrier between the bone and marrow compartments. On resorption surfaces, which were characterized by excavation cavities, …


Bone Lining Cells: Structure And Function, Scott C. Miller, Louis De Saint-Georges, Beth M. Bowman, Webster S. S. Jee Oct 1989

Bone Lining Cells: Structure And Function, Scott C. Miller, Louis De Saint-Georges, Beth M. Bowman, Webster S. S. Jee

Scanning Microscopy

Bone lining cells (BLC's) cover inactive (nonremodeling) bone surfaces, particularly evident in the adult skeleton. BLC's are thinly extended over bone surfaces, have flat or slightly ovoid nuclei, connect to other BLC's via gap junctions, and send cell processes into surface canaliculi. BLC's can be induced to proliferate and differentiate into osteogenic cells and may represent a source of "determined" osteogenic precursors. BLC's and other cells of the endosteal tissues may be an integral part of the marrow stromal system and have important functions in hematopoiesis, perhaps by controlling the inductive microenvironment. Because activation of bone remodeling occurs on inactive …


Osteoclast Features Of Cells That Resorb Demineralized And Mineral-Containing Bone Implants In Rats, Cedo M. Bagi, Scott C. Miller Oct 1989

Osteoclast Features Of Cells That Resorb Demineralized And Mineral-Containing Bone Implants In Rats, Cedo M. Bagi, Scott C. Miller

Scanning Microscopy

The comparative temporal tissue response to demineralized bone matrix powder (DBP) and devitalized mineral containing bone powder (MCP) implanted subcutaneously in rats was studied. The tissue response to implanted DBP followed the well described endochondral osteogenic pathway and included the appearance of osteoblasts and osteoclasts. On the other hand, implanted MCP resulted in the appearance of a large population of giant cells that resorbed the implants. At later times (3-4 weeks), most of the cells in the MCP implants appeared as typical foreign body giant cells with extensive membrane foldings, usually away from bone surface. Some cells did, however, have …


Structural And Compositional Changes In Aging Bone: Osteopenia In Lumbar Vertebrae Of Wistar Female Rats, M. Silbermann, M. Safadi, D. Schapira, I. Leichter, R. Steinberg Oct 1989

Structural And Compositional Changes In Aging Bone: Osteopenia In Lumbar Vertebrae Of Wistar Female Rats, M. Silbermann, M. Safadi, D. Schapira, I. Leichter, R. Steinberg

Scanning Microscopy

Changes in vertebral bone mineral content and density during aging were quantified in female Wistar rats. This study represents a longitudinal follow up utilizing single photon absorptiometry for the measurement of bone mineral content (BMC), quantitative computed tomography (OCT) for the measurement of bone mineral density (BMD), and image analysis histomorphometry for the measurement of trabecular bone volume (TBV) and bone cortical area (BCA). The above measurements were accompanied by biochemical assays of calcium concentrations in the respective bones. All aging animals experienced significant decreases in BMC, BMD, TBV, BCA and in the calcium content of their bones. The above …