Paul Goldhaber

Thyrocalcitonin inhibition of bone resorption induced by parathyroid hormone in tissue culture.

Added thyrocalcitonin greatly diminished parathyroid-hormone-induced resorption of bone in tissue culture. The results indicate that bone is primary site of action of thyrocalcitonin.

Successful treatment of hypercalcemia by indomethacin in mice bearing a prostaglandin-producing fibrosarcoma

Abstract Mice bearing the HSDM 1 fibrosarcoma have elevated concentrations of calcium and prostaglandin E 2 in serum. Extracts of tumor tissue contain high concentrations of bone resorption-stimulating activity and PGE 2 . Administration of indomethacin to tumor-bearing mice lowers serum calcium and PGE 2 levels, reduces in parallel tumor bone resorption-stimulating activity and PGE 2 content, and diminishes tumor size.

Changes in vasculature of the periodontium associated with tooth movement in the rhesus monkey and dog

Abstract Changes in the vasculature of the periodontal ligament (PDL) of dog or monkey teeth subjected to experimental orthodontic forces were demonstrated by a perfusion method, using Pelikan carbon black. After 24 hr of force application, compression resulted in partial or complete occlusion of the vessels in the PDL, while on the tension side the PDL vessels were considerably extended. Two days later the differences were less pronounced. Seven days after force application, increased vascularity was still present within the PDL on the tension side, now characterized by new bone formation. On the pressure side, where bone resorption was evident, the vasculature was reestablished. The density of the vessels exceeded that of control regions. These vascular alterations were similar to those found in apposition and resorption sites associated with physiologic mesial migration of posterior teeth of monkeys, and are considered typical for active formation and resorption of bone. Such obervations relate well to information gathered from in-vitro studies of bone.

Collagenase and bone resorption: isolation of collagenase from culture medium containing serum after stimulation of bone resorption by addition of parathyroid hormone extract.

Summary A new method is described for the isolation of tissue collagenase from culture medium containing serum. The method was used to isolate mouse bone collagenase from an in vitro tissue culture system utilizing mouse bone calvaria in which rapid bone resorption was stimulated by the addition of parathyroid hormone extract. The amount of collagenase activity in the tissue culture medium was found to correlate well with the extent of bone resorption observed morphologically. The results provide further and more direct evidence that the synthesis and release of bone collagenase is involved in and related to the removal of bone collagen during bone resorption.

Collagenolytic Activity During Active Bone Resorption in Tissue Culture.

Summary A tissue culture system has been used to study the release of collagenolytic activity from actively resorbing bone by measuring the degradation of purified, reconstituted H3-hydroxyproline- and H3-proline-labeled collagen fibrils. Under conditions where active bone resorption was observed morphologically, a collagenolytic factor was liberated from the bone which degraded reconstituted, undenatured collagen fibrils. This collagenolytic activity was increased by addition of parathyroid extract to the tissue culture medium, and still further enhanced when both parathyroid extract and heparin were added.

The Effect of Various Oxygen Tensions on The Synthesis and Degradation of Bone Collagen in Tissue Culture.

Summary The effect of various oxygen tensions on the synthesis and degradation of bone collagen has been studied biochemically in tissue culture. The incorporation of H3-proline from the tissue culture medium into collagen H3-hydroxyproline has been used as an index of collagen synthesis, and the release of hydroxyproline into the tissue culture medium as an index of collagen degradation. The results show that at low oxygen tensions the rate of collagen synthesis exceeds that of degradation. At higher oxygen tensions, both the rates of synthesis and degradation increase. At an oxygen tension of 50%, the rates of synthesis and degradation are approximately equal. Under the latter conditions evidence is also presented which suggests that the bone collagen present in the calvaria at the time of explantation is more susceptible to resorption than the collagen synthesized during culture.

The production of a bone resorbing factor by dental cysts in vitro.

Summary Vital explants of nine dental cysts and one ameloblastoma were maintained in tissue culture with mouse calvaria for seven days. Eight produced marked bone resorption which was not seen when devitalised tissue was similarly cultured. It is proposed that dental cyst and tumour growth within bone is dependent on the synthesis and release of a potent bone resorbing factor.

Mouse bone collagenase: Purification of the enzyme by heparin-substituted sepharose 4B affinity chromatography and preparation of specific antibody to the enzyme

Heparin-substituted Sepharose 4B gel, affinity chromatography used to purify mouse bone collagenase increased its specific activity 1340-fold (2850 units/mg) with an overall yield of 9% from the original pooled tissue culture medium. The purified enzyme moved as a single band and had a molecular weight of 47,000 as determined by analytical disc gel electrophoresis in the presence of 1% sodium dodecyl sulfate. Antiserum to the purified enzyme was produced in rabbits, and its monospecificity was established by immunoelectrophoresis. The γ-globulin fraction of the antiserum, freed of α 2 -macroglobulin by gel filtration, inhibited collagenase activity. The antibody was purified approximately 70-fold by immunoadsorption using enzyme-substituted Sepharose 4B gel. The extent of the immunoinhibition of various tissue collagenases by mouse bone collagenase antibody varied depending on the tissue and species from which the enzyme was obtained.

Studies on the interaction between heparin and mouse bone collagenase

Mouse bone collagenase was found to be tightly bound to a heparin-substituted gel at low ionic strength. The bond was reversible, however, and the collagenase could be elutted at high ionic strength. In addition to providing a method for purifying the enzyme with high yield, the results suggest that the strong ionic bond between heparin and collagenase may partially explain the mechanism wherein heparin enhances the activity of mouse bone collagenase.

Predicting Alveolar Bone Loss in Beagles Using Bone-seeking Radiopharmaceutical Uptake

Measurements of bone-seeking radiopharmaceutical uptake obtained at the beginning of this two-year study of beagles with periodontal disease were correlated with the amount of bone loss which occurred during the study. Uptake correlated with bone loss (r=.85), which suggests that uptake may be an indicator of future bone loss.