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Biomedical subjects

H Norimatsu

Publications and source records attributed to H Norimatsu.

10 recordsLinked to original sources
PubMed1992

Roles of various growth factors in growth of human osteosarcoma cells which can grow in protein-free medium.

The human osteosarcoma cell line (OST-1-PF) can grow in protein-free Coon's modified Ham's F12 medium. Growth of the cells in protein-free medium was partially density-dependent and partially depressed by medium change. An extract and conditioned medium of OST-1-PF cells contained high mitogenic activity for BALB/c3T3 cells. The growth factor in the cells was purified and identified as a basic fibroblast growth factor (bFGF)--like factor on the basis of its elution profile on heparin-affinity chromatography and the result of immunoblotting. An unidentified factor in a conditioned medium eliciting most of the DNA synthesis-stimulating activity showed a weak affinity for heparin. Various additions, including serum and growth factors, stimulated the growth of OST-1-PF cells in protein-free medium. Of these factors, epidermal growth factor (EGF), transforming growth factor-alpha (TGF-alpha), acidic fibroblast growth factor (aFGF) and bFGF were the most potent mitogens. High-affinity receptors of EGF and FGF were found on the surface of these cells. These results indicate that autonomous growth of OST-1-PF cells in protein-free medium is mainly controlled by an intracellular mechanism.

Cell Division↗
PubMed1991

A comparison of hip fracture incidence among native Japanese, Japanese Americans, and American Caucasians.

Hip fracture incidence rates among men and women of Japanese ancestry living on Oahu, Hawaii, from 1979 to 1981 were compared with rates for Japanese living on Okinawa, Japan, from 1984 to 1985. Both rates were further compared with those for various American Caucasian populations, including that of Rochester, Minnesota, from 1978 to 1982. Age-specific and cumulative (age 50-84 years) hip fracture rates among persons of Japanese ancestry were approximately half that of Caucasians for both sexes. Although diet and other cultural attributes of the Oahu group have become more westernized than the Okinawan population, there were no detectable differences in hip fracture rates between Oahu and Okinawa Japanese. Additional studies are needed to determine whether the observed differences in fracture rates between Caucasians and Japanese might be related to differences in bone mass, body size, frequency of falls, or other factors.

Adult↗
PubMed1989

Bone mineral density of the spine and proximal femur in normal and osteoporotic subjects in Japan.

Bone mineral density (BMD) of the spine and proximal femur in Japanese men and women was investigated with dual photon absorptiometry, using gadolinium-153. Peak bone mass of the spine (L2-4) was 1.20 g/cm2 in women which was lower than that of men by 4.7%, whereas BMD of the femoral neck was 0.91 g/cm2 in women and lower than in men by 13.3%. Bone loss was faster in postmenopausal women than in men of the corresponding age, and the regressions of BMD on age were 6.7-times higher at L2-4 and 5.1-times higher at the femoral neck than in men. Such rates of loss became slower both in the lumbar spine and proximal femur in women after 70 years of age, but the density at the proximal femur kept decreasing in men after 70 years of age. Fracture thresholds of each region were evaluated at the 90th percentile for BMD of L2-4 in patients with vertebral crush fractures and for BMD of the proximal femur in patients with hip fractures. The fracture threshold was 0.97 g/cm2 at the spine and 0.67 g/cm2 at the femoral neck in women. BMD values at the spine and proximal femur in normal Japanese men and women appear to be lower than those in white American control population.

Adult↗
PubMedDate not supplied

Electron microscopic study of the effects of calcitonin on bone cells and their extracellular milieu.

This is a scanning and transmission electron microscopic study of the changes produced by small doses of calcitonin (0.15 mU/g body weight) in the lining cells and their microenvironment at the endosteal surfaces of the tibia of neonate rats. The techniques used included "freeze substitution" preparation, staining with lead acetate, and with lanthanum added to the fixative. Rats were sacrificed 5, 15, and 30 minutes after subcutaneous injection of salmon calcitonin. The following observations were made; within 5 minutes following calcitonin injection, the response of the endosteal lining cells included increased numbers of microvilli and surface blebs. Cell contraction was apparent, including an irregular appearance of the plasma membrane and enlarged intercellular channel size, though cell-to-cell contact still occurred. By 15 minutes, following hormone injection, the cells were returning to normal morphology and were in close contact with each other. Calcitonin caused a marked accumulation of lanthanum around osteocytes and in bone fluid adjacent to lining cells. The lanthanum was found in large aggregates and appeared to "clump." Following "freeze substiuttion" preparation, the edge of the osteoid was bordered by what appeared to be mineral aggregates. We conclude that bone lining cells and osteocytes respond rapidly to low doses of calcitonin, thereby suggesting that they play a role in the physiological action of the hormone. This function includes a modification of the fluid microenvironment of these cells, possibly providing a site for temporary storage of calcium.

Animals↗