Histochemical detection of osteocalcin in normal and pathological human bone.

We investigated the immunohistochemical localization of osteocalcin in demineralized, paraffin-embedded normal and pathological human bone. Acid decalcification protocols appeared to be more suitable for osteocalcin detection than mild chelating agents. In normal lamellar bone, osteocalcin was detected in osteocytes and along the lamellar bone matrix in fine granular deposits. Under pathological conditions (osteomyelitis, neoplasia), appositional bone showed immunoreactivity in osteoblasts and osteocytes but not in the provisory woven bone matrix. Intense immunoreactivity could be seen at the cell borders of osteoclasts and the bone margins of Howship lacunae. In primary bone-forming tumors, osteocalcin immunoreactivity was detected in osteoblasts and their malignant counterparts. On the basis of these results, we conclude that optimal preservation of osteocalcin is obtained through mild acid decalcifiers. Osteocalcin is deposited in bone matrix, especially that of metabolically inactive bone. In neoplasms, osteocalcin could be a marker of osteoblastic differentiation.

Prostaglandin synthesis by osteoid osteoma and osteoblastoma.

Osteoid osteomas are characterized clinically by a pattern of nocturnal pain which is exquisitely sensitive to salicylates. Etiology for the pain has been ascribed by previous investigators to the presence of nonmyelinated nerve fibers or to the effect of prostaglandins. In an effort to corroborate the potential role of prostaglandins in mediating the pain associated with this tumor, we have determined the concentration of prostaglandins E2, F2 alpha, 6-keto-F1 alpha, and thromboxane B2 utilizing radioimmunoassay of extracts of homogenated tumor tissue. Results were compared with similar extracts of normal bone and a variety of other osseous tumors. The increased concentrations of prostaglandin E2 found in cases of osteoid osteoma and osteoblastoma confirm studies of explants of these tumors previously recorded in the literature.

[Trace elements of bone tumors]. / Mikroélementy opukholei kostei.

Due to activation analysis involving the use of neutrons from a nuclear reactor, the concentrations of 11 trace elements: scandium, iron, cobalt, mercury, rubidium, selenium, silver, antimony, chrome, zinc and terbium in intact bone and skeletal tumors were measured. 76 specimens of bioptates and resected material of operations for bone tumors and 10 specimens of normal bone tissue obtained in autopsies of cases of sudden death were examined. The concentrations of trace elements and their dispersion patterns in tumor tissue were found to be significantly higher than those in normal bone tissue. Also, the concentrations of some trace elements in tumor differed significantly from those in normal tissue; moreover, they were found to depend on the type and histogenesis of the neoplasm.

Ultrastructure of osteoblastoma.

The ultrastructure of three cases of osteoblastoma is described. The osteoblasts resemble normal osteoblasts with a few exceptions: irregular, indented nuclei, and occasional mitochondria with curved cristae and electron-lucent areas. The osteocytes and osteoclasts basically resemble their normal counterparts. There are also osteoprogenitor cells in different stages of maturation, some containing glycogen. The ultrastructure of an additional case histologically classified as aggressive osteoblastoma is described. It is essentially similar to the previous three cases of typical osteoblastoma. The only exception is the presence of osteoblasts with electron-lucent nuclei and less prominent organelles than the typical osteoblastoma cells have markedly indented and multilobed nuclei, dilated rough endoplasmic reticulum and lipid droplets. However, these differences from osteoblastoma cells are not pathognomonic. The final diagnosis of osteoblastic tumors rests at the light microscopy level.