Metabolic bone disease & related research最新文献

Osteoclasts were isolated from the long bones of chicks by a nylon mesh filtering system. The cell purity, in terms of area of the slide occupied, was on the average 77.5% osteoclasts, 22% aggregated osteoblasts and matrix debris, and 1.5% individual blood and marrow cells. Viability, as measured by cytochalasin-blockable phagocytosis, of up to 99% was obtained. Electron microscopic examination revealed good retention of ultrastructural features. The presence of carbonic anhydrase and acid phosphatase in osteoclasts was verified by selective staining methods; the aggregates were positive for alkaline phosphatase. Carbonic anhydrase activity was 0.89 ± 0.13 × 10⁻⁴ micro Wilbur-Anderson units per osteoclast, and red blood cells had 0.12 ± 0.03 × 10⁻⁴ units/cell. Neither calcitonin nor parathyroid hormone influenced the activity of carbonic anhydrase. A review of other hormonal effects on carbonic anhydrase is provided.

A case of vanishing bone disease is presented, with radiologic, endoscopic, and peritoneoscopic evidence of angiomatous involvement of the bones, surrounding soft tissues, and gastrointestinal tract. The diagnosis was made by a combination of radiologic techniques and endoscopy. Areas of absent bone were shown to opacify after intralymphatic injections of contrast material, providing in vivo demonstrations that these areas of vanishing bone are occupied by abnormal lymphatics. The etiology remains obscure, but our review of the literature suggests that this condition may be one of a large spectrum of disorders due to a basic underlying endothelial dysplasia. The lymphatic system, vascular system, or both may be involved, and the condition may manifest itself as an abnormality of the bones, soft tissues, viscera, or a combination of these.

This study was carried out to describe in quantitative terms histologic parameters from selected regions of the cancellous bone in the normal femoral head. Femoral heads were obtained at autopsy, and blocks from the principal compressive (PC) and principal tensile (PT) regions of a coronal slide were sampled systematically to prepare 10 μm sections for automated histoquantitation using a Quantimet image analyzer. For mineralized bone there was a significant negative regression on age in both principal stress regions, though the quantitative description was not definitive. The principal compressive values of mineralized bone were higher, with no sex difference, compared to the principal tensile values, which showed a sex difference. Changes in trabecular surface, width, and marrow spacing were shown to be more dependent on bone mass than on age. The surface density values were higher, without sex difference for the PC region compared to the PT region, which had a sex difference. There was no regression on age for the PC region but a significant negative regression for the PT region. For mean trabecular thickness, again the values were higher for the PC region, with negative regressions on age for both regions but no sex difference in either region. For spacing, the values were lower for the PC region, with a significant increase with age for both regions but no sex difference in either region. The surface density had positive linear regressions on mineralized bone for both PC and PT regions, though a parabolic regression, based on a model described, was favored. Trabecular width and spacing for PC and PT regions showed significant positive and negative regressions on mineralized bone, respectively.

The heterogeneous nature of the structural data, between regions, suggests the existence of different mechanical effectors that determine the structural architecture of the femoral head. While trabeculae are lost sooner in the principal tensile region than in the principal compressive region, trabecular thickness changes occur at the same rate in both principal stress regions. Moreover, principal tensile trabeculae are lost earlier because the mass of bone in the tensile region is less than that which is found in the compressive region.

Osteoclasts and macrophages in endochondral bone of rats were analyzed after long-term treatment with hydrocortisone (HC) or elcatonin (ECT). The growth plate-metaphysic junction (GPMJ) of the HC-treated bones showed increases numbers of osteoclasts, but the incidence of osteoclas profiles with ruffled borders was low and the cells had fewer nuclei. The number of macrophages in the GPMJ of HC-treated bone did not significantly differ from that in the control. In the metaphyseal trabecular (MT) regior macrophages were numerous, but osteoclasts were depleted.

Compared to controls the ECT treated osteoclasts in the GPMJ had an increased number of nuclei per cell, and the incidence of osteoclast profiles with ruffled border: was reduced. There was a small increase in the number of osteoclasts and a large increase in the number of macro phages. The osteoclasts in the MT regions of ECT treated bones were significantly larger compared to controls. The macrophages did not differ in number from the controls.

This investigation supports the proposal that the GPM is the principal site of osteoclast neogenesis. Discrepancies in features of osteoclasts in the GPMJ and MT regions of each treatment group were probably due to a difference in period when the osteoclasts were exposed to the drugs.

Since nontraumatic osteonecrosis of the femoral head is usually considered primarily as an ischemic disease, blood flow has been studied in femoral segments in two groups of geese, one control group and the other treated with a high dose of corticosteroïds for 5 months. There was no histologic evidence of osteonecrosis in femoral heads, and mean bone blood flow in any femoral segments was not reduced in the treated group. These results suggest that osteonecrosis of the femoral head is not caused primarily by ischemia, even if ischemia may play a secondary role in the evolution of the disorder.