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P29. Continuous motion parallax in the display and analysis of trabecular bone structure
228 assessment of fibre orientations with respect to the plane of section. Colour coding of uniform grey level slices provides the most interpretable display of the fibre orientation pattern. The collagen orientation pattern for a large bone section can now be determined in seconds as opposed to hours for previous methods. The reproducibility of the technique is good with a coefficient of variation of 3% obtained for the same section imaged on 11 separate occasions. A striking correlation between collagen orientation and in vivo strain can be seen in the equine radius.
P28. Scanning electron microscopy of vascular
mineralising cartilage in developing antler A Boyde, T R Arnett, C M Gray, A S I Loudon and E Maconnachie Department of Anatomy and Developmental Biology, University College London, Gower Street, London WClE 6BT We have undertaken a detailed study of growing antlers, the fastest growing organs composed of mineralised tissues. The methods of study combined routine histology with confocal LM of vital tissue, and SEM methods for 3-D morphology of matrix surfaces and mineralising and resorbing fronts with density imaging. The fast longitudinal growth depends on the proliferation of pre-chondroblastic cells and their further division and hypertrophy creating an extensive cartilaginous zone in which there is no mineralisation. It is not surprising, therefore, that this tissue is richly vascularised throughout. This is in contrast to the growth plates of long bones of most post-natal mammals where vascular invasion (rather than inclusion) is often held to be confined to, and associated with, the level of mineralisation of the intercolumnar cartilage matrix. Antler thus constitutes an extreme “model” of a highly polarised, mineralising vascular cartilage. The formation of an unusually high cell-volume-fraction mineralised cartilage occurs alongside pre-existing longitudinal blood vessel channels. Another interesting feature is the rapid proliferation of pre-osteogenic tissue around the core of mineralised cartilage. At least in some species, this gives rise to the formation of primary
Abstracts from the Bone and Tooth Society Meeting (woven), densely mineralised bone which may be a considerable fraction of the initially formed hard tissue. This rapid “periosteal” growth incorporates other longitudinal vessels. The extent of partial resorption and replacement of both primary bone and calcified cartilage is also extremely impressive.
P29. Continuous motion parallax in the display and analysis of trabecular bone structure A Boyde, R Radcliffe, T F Watson and J A I’ Jayasinghe Department of Anatomy and Developmental Biology, University College London, Gower Street, London WC1 E 6BT We are seeking new approaches of microscopic analysis in a continuing attempt to improve upon prior methods of characterising the thinning and loss of trabeculae in post-menopausal osteoporosis. We reject those methods which result in wholesale destruction of the residual continuity of bone structure, and consider only those which can lead to the reconstruction of a large part of the largest volume through which some unscattered visible light or electrons will pass. Compromising between the normal premenopausal and late osteoporotic conditions of trabecular bone from the femoral neck and lumbar vertebral bodies, we arrive at a 5mm diameter rod as a standard sample. The samples are cleaned with an enzyme detergent, defatted with chloroform-methanol and dried - stages of preparation common to SEM and range imaging with confocal microscopes. To secure the 360” range of projections necessary to capture all possible views from one rotation, the sample is mounted on the axis of a slowly rotating shaft, which is also moved continuously along its long axis. The image from a low magnification LM with extreme depth of field (Olbrich 4000) is displayed via a high resolution TV camera and monitor, and recorded for playback analysis. This dynamic display of motion parallax information (X, Y and time: instead of X, Y and Z) leads to a powerful 3-D impression which is of great benefit in interpreting the complexities of trabecular bone architecture.
Acknowledgments: The Society gratefully acknowledges the assistance of Rorer Pharmaceuticals, Sandoz Pharmaceuticals and Ciba-Geigy Pharmaceuticals.
P28. Scanning electron microscopy of vascular
mineralising cartilage in developing antler A Boyde, T R Arnett, C M Gray, A S I Loudon and E Maconnachie Department of Anatomy and Developmental Biology, University College London, Gower Street, London WClE 6BT We have undertaken a detailed study of growing antlers, the fastest growing organs composed of mineralised tissues. The methods of study combined routine histology with confocal LM of vital tissue, and SEM methods for 3-D morphology of matrix surfaces and mineralising and resorbing fronts with density imaging. The fast longitudinal growth depends on the proliferation of pre-chondroblastic cells and their further division and hypertrophy creating an extensive cartilaginous zone in which there is no mineralisation. It is not surprising, therefore, that this tissue is richly vascularised throughout. This is in contrast to the growth plates of long bones of most post-natal mammals where vascular invasion (rather than inclusion) is often held to be confined to, and associated with, the level of mineralisation of the intercolumnar cartilage matrix. Antler thus constitutes an extreme “model” of a highly polarised, mineralising vascular cartilage. The formation of an unusually high cell-volume-fraction mineralised cartilage occurs alongside pre-existing longitudinal blood vessel channels. Another interesting feature is the rapid proliferation of pre-osteogenic tissue around the core of mineralised cartilage. At least in some species, this gives rise to the formation of primary
Abstracts from the Bone and Tooth Society Meeting (woven), densely mineralised bone which may be a considerable fraction of the initially formed hard tissue. This rapid “periosteal” growth incorporates other longitudinal vessels. The extent of partial resorption and replacement of both primary bone and calcified cartilage is also extremely impressive.
P29. Continuous motion parallax in the display and analysis of trabecular bone structure A Boyde, R Radcliffe, T F Watson and J A I’ Jayasinghe Department of Anatomy and Developmental Biology, University College London, Gower Street, London WC1 E 6BT We are seeking new approaches of microscopic analysis in a continuing attempt to improve upon prior methods of characterising the thinning and loss of trabeculae in post-menopausal osteoporosis. We reject those methods which result in wholesale destruction of the residual continuity of bone structure, and consider only those which can lead to the reconstruction of a large part of the largest volume through which some unscattered visible light or electrons will pass. Compromising between the normal premenopausal and late osteoporotic conditions of trabecular bone from the femoral neck and lumbar vertebral bodies, we arrive at a 5mm diameter rod as a standard sample. The samples are cleaned with an enzyme detergent, defatted with chloroform-methanol and dried - stages of preparation common to SEM and range imaging with confocal microscopes. To secure the 360” range of projections necessary to capture all possible views from one rotation, the sample is mounted on the axis of a slowly rotating shaft, which is also moved continuously along its long axis. The image from a low magnification LM with extreme depth of field (Olbrich 4000) is displayed via a high resolution TV camera and monitor, and recorded for playback analysis. This dynamic display of motion parallax information (X, Y and time: instead of X, Y and Z) leads to a powerful 3-D impression which is of great benefit in interpreting the complexities of trabecular bone architecture.
Acknowledgments: The Society gratefully acknowledges the assistance of Rorer Pharmaceuticals, Sandoz Pharmaceuticals and Ciba-Geigy Pharmaceuticals.