Biomedical subjects

S Doppelt

Publications and source records attributed to S Doppelt.

4 recordsLinked to original sources

PubMed1989

Bone and bone marrow changes in Gaucher disease: evaluation with quantitative CT.

The trabecular bone density and bone marrow fat content in eight patients with type 1 Gaucher disease were measured with the use of a modification of dual-energy computed tomography (CT). The results were compared with those in published reports of single-energy quantitative CT measurements in healthy subjects and with dual-energy data obtained in studies of healthy premenopausal women and elderly osteopenic women. The trabecular bone mass was moderately decreased in patients with Gaucher disease. The bone marrow fat content was markedly diminished, presumably due to replacement of marrow fat by Gaucher cells. In healthy and osteopenic subjects single-energy quantitative CT values were lowered by the presence of marrow fat. Comparable single-energy measurements in patients with Gaucher disease reflect greater degrees of bone loss. Low levels of marrow fat may prove to be a valuable marker of the severity of marrow disease.

Absorptiometry, Photon↗

PubMed1986

Evaluation of Gaucher disease using magnetic resonance imaging.

Magnetic resonance imaging was used to study the skeletal involvement in a series of twenty-four patients with Gaucher disease. Many sites in the marrow of these patients were characterized by an abnormally low signal intensity that reflected shortened T1 and markedly shortened T2 values in the replaced marrow. The abnormality was non-homogeneous in distribution. In the lower extremity, the proximal (femoral) areas were more frequently affected than the distal (tibial) sites. The epiphyses were generally spared unless the involvement of bone was extensive. Lack of epiphyseal involvement on the magnetic resonance images generally precluded any suspicion of osteonecrosis. The extent of involvement, as suggested by the magnetic resonance data, appeared to correlate well with the occurrence of musculoskeletal complications. Magnetic resonance imaging is more sensitive than computerized tomography in demonstrating the extent of abnormalities in patients with Gaucher disease, and it may have prognostic value.

Adolescent↗

PubMed1984

Protamine: a powerful in vivo inhibitor of bone resorption.

Protamine is shown to be a powerful disrupter of calcium homeostasis, acutely inducing a severe hypocalcemia in both rabbits and rats. The magnitude of its effect correlates with bone turnover. Protamine does not significantly alter the renal excretion of calcium, and is effective whether or not there is calcium present in the gut. Protamine causes a significant fall in the specific activity of 45Ca in the blood in animals whose bone has been prelabeled with 45Ca. These data suggest that protamine induces hypocalcemia by blocking calcium efflux from bone. Further work seems indicated to define the biochemical mechanism of this action.

Animals↗

PubMed1983

Clinical experience with allograft implantation. The first ten years.

Since 1971 the Orthopaedic Oncology Service at the Massachusetts General Hospital has performed 150 resections and allograft implantations for the management of mostly tumorous bone conditions. The procedures used cadaveric segments harvested from donors and stored at -80 degrees after exposure of the cartilage to 10% glycerol as a cryopreservative. Following resection of the tumor, the selected part was implanted and held with plates and screws or intramedullary rods, and the patients were observed closely for alterations suggestive of "rejection" (none was seen), presence of recurrences or metastases, functional status of the part, and relationship of complications to outcome. Of 91 patients followed up for two or more years, the grafts performed acceptably (excellent or good functional result) in 70% or more. The results were better in patients with low-grade tumors or benign conditions and in resections and transplantations that did not involve a joint. Complications were a major factor in determining outcome. In patients with skin sloughs (9 patients), infection (13.2%), and, to a lesser extent, allograft fracture (16.5%), the prognosis for retention of the graft and functional restoration was compromised, but nonunion or delayed union (11%) had little effect on end results. The program remains somewhat experimental, in that continued research is required to improve the predictability of bony revascularization and the viability of articular cartilage, and to avoid the problems associated with infection and fracture.

Adolescent↗