Morio Higaki

Bone trabecular pattern analysis in Down's syndrome with the use of computed panoramic tomography with a laser scan system: Quantitative analysis with the power spectrum method

A quantitative analysis of the mandibular bone trabeculae of 44 patients with Downs syndrome and 68 normal persons by means of panoramic tomography was performed with a laser scan system. The results showed that the normal persons exhibited a correlation between the trabecular pattern and aging, whereas the patients with Downs syndrome showed no such correlation. These findings were consistent with geromorphism, which is one of the systemic features of Downs syndrome.

Identification of osteoblast-specific monoclonal antibodies

SummaryA series of four antibodies against rat osteoblasts have been produced using the hybridoma technique. After bone cells isolated from newborn rat calvariae by a sequential digestion procedure were cultured for 3 days, the cells were trypsinized and further maintained in rotation cultures overnight. Out of the cultured bone cells alkaline phosphatase-positive cells were sorted by flow cytometry and used as immunogens. The clones secreting the antibodies were selected on the basis of the abilities of these antibodies to bind to the bone cells but not to fibroblasts from neonatal rat head skins, in an enzyme-linked immunosorbent assay. Clones of two hybridomas, designated AOB-1 and AOB-2, were used to characterize the antigenic determinant(s) in osteogenic cells. The antibody showed the reactivity with isolated alkaline phosphatase-positive cells, osteogenic tissue cells in newborn rat calvaria, and mandibula, but not with the cells in head skin, lung, kidney, liver, or stomach as determined by immunofluorescence study. Western blot analysis has identified the antigenic determinants possessing apparent molecular weights of 210,000, 110,000, 65,000, 58,000, 40,000, 36,000, 32,000, 28,000, 25,000, 17,000, and 15,000 of osteoblast-rich monolayer cultured cells. According to the cell surface detection with biotin-avidin protein blotting technique, these fractions appear to be present as components of the cell surface of the osteoblast.