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1997 Fiscal Year Final Research Report Summary

Cerebral hemodynamic in so-called 'netakiri roujin'

Research Project

Project/Area Number 08670051
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field General physiology
Research InstitutionTottori University

Principal Investigator

KAWAI Yasuaki  Tottori Univ., Faculty of Med., Professor, 医学部, 教授 (70143972)

Project Period (FY) 1996 – 1997
Keywordscelebral circulation / intracranial pressure / brain edema / ocular circulation / laser-Doppler / near infrared / gravity / 重力
Research Abstract

Two series of experiments were carried out to invetigate the cerebral hemodynamics in so-called 'netakiri-roujin', old persons who have only few occasions to get up. 1. Acute responses of brain oxygenation during postural change were studied in humans using near infrared spectroscopy. 2. Animal experiments were carried out to observe the time course of cerebral and ocular hemocynamics before, during and after exposure to head-down tilt. Cerebral and ocular blood flow were measured by lase-Doppler flowmetry. Intracranial pressure was measured by a pressure transducer via a catheter inserted into the subarchnoid space or the cisterna magna. Intraocular pressure was measured by both needle insertion technique (invasive) and tono-pen tonometry (non-invasive). The present results suggest :
1) Cerebral blood flow increases right after exposure to head-down tilt (-6゚C in humans and -45゚C in animals), then gradually decreases toward the baseline.
2) Increase in intracranial pressure may play a major role in the reduction of cerebral blood flow during the time course of head-down tilt. The elevation of intracranial pressure during head-down tilt is probably due to accumulation of blood in the intracranial veins and shift of cerebrospinal fluid from outside to inside the cranium. Formation of edema is not involved in the acute response of intracranial pressure, but it may further increase the pressure in a chronic stage of head-down tilt.
3) Qualitatively similar results are obtained in the ocular circulation, including transient increase in ocular blood flow and sustained elevation of intraocular pressure.
Thus, long-lasting bed rest with only few occasions to get up may cause sustained reduction of cerebral blood flow, elevation of intracranial presure, and edema formation which, in turn, possibly affect the brain function.

  • Research Products

    (12 results)

All Other

All Publications (12 results)

  • [Publications] Y.KAWAI: "Acute responses of brain oxygenation during postural change in humans" 6th World Congress for Microcirculation. 697-701 (1996)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] M.Doi: "Effect of head-down tilt on cerebral circulation and intracranial pressure in rabbits" 6th World Congress for Microcirculation. 103-107 (1996)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] A.SETOGAWA: "Acute changes in ocular microcirculation and intraocular pressure during head-down tilt in rabbits" 6th World Congress for Microcirculation. 133-136 (1996)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Y.KAWAI: "Cerebral hemodynamics during simulated microgravity in humans and rats" Adaptation Biology and Medicine. 1. 155-162 (1997)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] M.DOI: "Mechanisms of increased intracranial pressure in rabbits exposed to head-down tilt" Japanese Journal of Physiology. 48. 63-69 (1998)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] A.SETOGAWA: "Measurement of intraocular pressure by both invasive and non-invasive techniques in rabbits exposed to head-down tilt" Japanese Journal of Physiology. 48. 25-31 (1998)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Kawai Y,Okuda Y & Ogura K: "Acute responses of brain oxygenetion during postural change in humans." 6th World Congress for Microcirculation. 697-701 (1996)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Doi M.Setogawea A,Matsuura K & Kawai Y.: "Effects of head-down tilt on cerebral microcirculation and intracranial pressure in rabbits." 6th World Congress for Microcirculation. 103-107 (1996)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Setogawa Akira, Setogawa Akiko, matsuura K,Doi M & Kawai Y: "Acute changes in ocular microcirculation and intraocular pressure during head-down tilt in rabbits." 6th World Congress for Microcirculation. 133-136 (1996)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Kawai Y,Doi M,Matsuura K,Setogawa A,Hargens AR,Murthy G,Ballard RE & Watenpaugh DE: "Cerebral hemodynamics during simulated microgravity in humans and rats." Adaptation Biology and Medicine. 1. 155-162 (1997)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Doi M & Kawai Y: "Mechanisms of increased intracranial pressure in rabbits exposed to head-down tilt." Japanese Journal of Psysiology. 48. 63-69 (1998)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Setogawa A & Kawai Y: "Measurement of intraocular pressure by both invasive and noninvasive techniwque in rabbits exposed to head-down tilt." Japanese Journal of Psysiology. 48. 25-31 (1998)

    • Description
      「研究成果報告書概要(欧文)」より

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Published: 1999-03-16  

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