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The Regulatory Mechanism of the Intracellular Signal Transduction with Physical Stress for Bone Tissues.

Research Project

Project/Area Number 07671629
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field Orthopaedic surgery
Research InstitutionOSAKA MEDICAL COLLEGE

Principal Investigator

YAMAGUCHI Jun  REHABILITATION CENTER,KECTURER, 医学部, 講師 (20239891)

Project Period (FY) 1995 – 1996
Project Status Completed (Fiscal Year 1996)
Budget Amount *help
¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1996: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1995: ¥1,500,000 (Direct Cost: ¥1,500,000)
Keywordsosteoblast / patch-clamp / ion channel / protein kinase C / osteoporosis / ultrasound bone densitometry / ADL / hemiplegia / 脳卒中片麻痺 / 細胞培養 / 超音波骨密度測定法
Research Abstract

(1) To elucidate the electrophysiological properties of osteoblasts, we investigated the regulatory mechanism of chloride channel activity in a clonal osteoblastic cell line with the patch-clamp technique. In most of the insideout patches, the channel was activated only at a holding potential of around 0 mV,and was inactivated when the membrane potential was changed to a positive or a negative value. The voltage-dependency of channel activity was sensitive to intracellular Ca^<2+>. The single-channel conductance was about 340pS.The channel current was blocked by DIDS,reversibly at 10muM and irreversibly at 100muM.The channel was activated a few minutes after the excision of membrane patches in the absence of ATP.In presence of ATP (3mM), polymyxin B (20muM), an inhibitor of protein kinase C (PKC), activated the channel, but TPA (0.1muM) and OAG (1muM), potentactivators of PKC,inactivated the channel. Intracellular Ca^<2+> was not necessarily required for the channel activation, but it … More enhanced channel activity. The channel activation was found to be unaffected by okadaic acid (10muM), a specific inhibitor of types 1 and 2A phosphoprotein phosphatases.
These results suggest the following conclusion. In the presence of ATP,the channel protein or its related protein is phosphorylated by PKC,and the channel is inactivated and closes. In the absence of ATP,the protein is dephosphorylated probably by phosphoprotein phosphatases other than types 1 and 2A,and the channel is activated and opens. This reaction may be stimulated by Ca^<2+>.
(2) To investigate the relation of calcaneal bone atrophy to vertebral fracture and daily locomotion activity, we allied the ultrasound bone densitometry of the os calcis to osteoporotic patients in a rehabilitation hospital. In each subject, speed of sound (SOS) and broadband ultrasound attenuation (BUA) of the os calcis were measured with Achilles ultrasound bone densitometer (Lunar Corp.), and "Stiffness", an index of calcaneal bone atrophy, was defined from SOS and BUA.In this study, we examined the relation of Stiffness value to old compression fractures in vertebrae and daily locomotion activity. The mean Stiffness value of the osteoporotic patients was signeficantly lower than that of the normal control, and the mean value of the osteoporotic patients with old vertebral fracture was significantly lower than that without fracture. As for the daily locomotion activity, the value of the inpatients was significantly lower than that of the outpatients. The value of the patients with wheelchair activity was significantly lower than that with cane gait, and the value with cane gait was significantly lower than that with independent gait). There were statistically significant difference among the wheelchair activity, the cane gait, and the independent gait, respectively.
These suggest that ultrasound bone densitometry of the os calcis, which may fairly reflect the presence of old vertebral fracture and the state of daily locomotion activity, will be very useful both for risk-diagnosis of vertebral fracture and for rehabilitation program in osteoporosis. Less

Report

(3 results)
  • 1996 Annual Research Report   Final Research Report Summary
  • 1995 Annual Research Report
  • Research Products

    (11 results)

All Other

All Publications (11 results)

  • [Publications] 山口淳: "高槻市における骨粗鬆症予防教室について-健康教室としての踵骨の骨定量-" 第2回骨ドック・検診研究会プログラム抄録集. 19 (1996)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1996 Final Research Report Summary
  • [Publications] 山口淳: "骨粗鬆症患者の踵骨の骨萎縮度と脊椎骨折の既往ならびに日常の活動性に関する検討" 第5回日本骨粗鬆症研究会プログラム抄録集. 95 (1996)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1996 Final Research Report Summary
  • [Publications] 山口淳: "培養骨芽細胞における陰イオンチャネルの活性特性について-パッチクランプ法によるクロライドチャネルの同定-" 日本骨代謝学会雑誌. 14巻2号. 141 (1996)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1996 Final Research Report Summary
  • [Publications] 山口淳: "骨粗鬆症患者の踵骨の骨萎縮度と日常の活動性に関する検討" リハビリテーション医学. 33巻12号. 1023-1024 (1996)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1996 Final Research Report Summary
  • [Publications] 山口淳: "骨粗鬆症患者の踵骨の骨萎縮度と脊椎骨折の既往に関する検討" リハビリテーション医学. 33巻12号. 1023 (1996)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1996 Final Research Report Summary
  • [Publications] 山口淳: "高槻市における骨粗鬆症予防教室について-健康教室としての踵骨の骨定量-" 第2回骨ドック・健診研究会プログラム抄録集. 19 (1996)

    • Related Report
      1996 Annual Research Report
  • [Publications] 山口淳: "骨粗鬆症患者の踵骨の骨萎縮度と脊椎骨折の既往ならびに日常の活動性に関する検討" 第5回日本骨粗鬆症研究会プログラム抄録集. 95 (1996)

    • Related Report
      1996 Annual Research Report
  • [Publications] 山口淳: "培養骨芽細胞における陰イオンチャネルの活性特性について-パッチクランプ法によるクロライドチャネルの同定-" 日本骨代謝学会雑誌. 14巻2号. 114 (1996)

    • Related Report
      1996 Annual Research Report
  • [Publications] 山口淳: "骨粗鬆症患者の踵骨の骨萎縮度と日常の活動性に関する検討" リハビリテーション医学. 33巻12号. 1023-1024 (1996)

    • Related Report
      1996 Annual Research Report
  • [Publications] 山口淳: "骨粗鬆症患者の踵骨の骨萎縮度と脊椎骨折の既往に関する検討" リハビリテーション医学. 33巻12号. 1023 (1996)

    • Related Report
      1996 Annual Research Report
  • [Publications] 山口 淳: "超音波法による踵骨の骨定量「日常の活動性および脊椎骨折の既住に関する検討」" リハビリテーション医学. 32巻. 961 (1995)

    • Related Report
      1995 Annual Research Report

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Published: 1995-04-01   Modified: 2016-04-21  

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