| Project/Area Number |
06454586
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
矯正・小児・社会系歯学
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| Research Institution | Nihon University |
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Principal Investigator |
IWASAWA Tadamasa Nihon Univ., Sch.of Dent.at Matsudo, Dept.of Orthodontics, Professor, 松戸歯学部, 教授 (30050016)
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| Co-Investigator(Kenkyū-buntansha) |
SAITO Kayo Nihon Univ., Sch.of Dent.at Matsudo, Dept.of Orthodontics, Subassistant, 松戸歯学部, 副手 (30205637)
SHIMIZU Noriyoshi Nihon Univ., Sch.of Dent.at Matsudo, Dept.of Orthodontics, Assistant Professor, 松戸歯学部, 講師(専任扱) (40154299)
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| Project Period (FY) |
1994 – 1995
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| Project Status |
Completed (Fiscal Year 1995)
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| Budget Amount *help |
¥3,700,000 (Direct Cost: ¥3,700,000)
Fiscal Year 1995: ¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 1994: ¥2,200,000 (Direct Cost: ¥2,200,000)
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| Keywords | Low-power laser / Bone nodul / Rat calvarial cell / Differentiation / bone formation / osteoblast / bone nodule |
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| Research Abstract |
Effects of low-power laser irradiation on bone nodule formation in vitro were assessed. Osteoblast-like cells isolated from rat calvariae of rat fetuses were cultured and were irradiated with a low-power laser for 10 min per day. Both every day and pulsed laser irradiation significantly increased the number of bone nodules formed in a dish. When pulsed irradiation was performed within 1 to 13 d after subculture, bone nodule formation significantly increased. However, irradiation had no effects on bone nodule formation when laser was irradiated after 14 d of subculture. Furthermore, irradiation was performed in the earlier period (within 13 d) after subculture to the cells resulting in larger average size of bone nodules. It is most likely that laser irradiation stimulated differentiation and proliferation of the cells in the earlier period and these cells formed a larger number and size of bone nodules. Therefore, laser irradiation to immature osteoblasts, but not mature osteoblasts ma
… More
y effective to stimulate bone nodule formation.
The extra-cellular collagen level and alkaline phosphatase (ALP) activity were increased by laser irradiation and increased rates were 20 to 30% suggesting that osteoblasts function may be also stimulated by laser irradiation. When Ca and P contents in mineralized nodules were assessed by JEOL JED-2000 energy-dispersive X-ray microanalyzer, net intensities of Ca and P were significantly higher (Ca : 1.3 fold ; P : 1.3 fold) in laser group than in control group. However, the mean values of Ca/P mole ratio were similar in both groups. It may show that laser irradiation stimulated mineralization of bone nodules.
Effects of pulsed laser irradiation (10min) on gene expression of type 1 collagen and ALP were investigated using RT-PCR method. Gene expression of both collagen and ALP increased 24 h after laser irradiation compared to those in the controls. These data suggest that laser irradiation may directly affect cells and stimulate differentiation and function of rat calvarial cells resulting a large number and size of bone nodule formation. Less
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