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1992 Fiscal Year Final Research Report Summary

MRS studies on protective reactions of neonatal cerebral neurons against acidosis

Research Project

Project/Area Number 03670503
Research Category

Grant-in-Aid for General Scientific Research (C)

Allocation TypeSingle-year Grants
Research Field Pediatrics
Research InstitutionKyoto Prefectural University of Medicine

Principal Investigator

YOSHIOKA Hiroshi  Kyoto Prefectural University of Medicine Department of Pediatrics Assistant Professor, 医学部, 講師 (50128724)

Co-Investigator(Kenkyū-buntansha) HASEGAWA Ko  Kyoto Prefectural University of Medicine Department of Pediatrics Assistant Prof, 医学部, 助手 (80228444)
Project Period (FY) 1991 – 1992
KeywordsAcidosis / Hypoxia / Neonate / Neuron / Magnetic resonance / Protective reaction
Research Abstract

1. Cerebral energy metabolism in newborn mice was investigated during and after 8-hour hypoxia produced by exposure to a 5% oxygen, 95% nitrogen mixture by 31P magnetic resonance spectroscopy. PCr/Pi ratio decreased from a control value of 1.55 to 0.56 at the end of hypoxia. The brain intracellular pH (pHi) increased from 7.20 to 7.36 within 1 hour and stayed higher than control throughout the hypoxic period. The control value of mixed arterial and venous blood pH (pHb) was 7.39. pHb decreased immediately after the induction of hypoxia and fell to 7.16 at the end of hypoxia. These results suggest that there may be an unknown protective system in neonatal brain against systemic acidosis.
2. The effects of hypercapnic acidosis on neuronal activity and mitochondrial respiration were studied in the neonatal canin brain with EEG and 31P-MRS. Inspired CO2 levels of 13, 20, and 30% were administered through a ventilator and resulted in 3 levels of hypercapnia where measured PaCO2 values were approximately 70, 100, 140mmHg. pHi was reduced from 7.11 to 6.99, 6.87, and 6.76 in response to the increasing levels of hypercapnia, and free ADP decreased from 21.5 to 18.1, 14.8 and 12.9uM. The cerebral electrical activity was reduced by 20, 30, and 40%. The change in ADP concentration with respect to EEG output was fitted with the Michaelis-Menten relationship for the mitochondrial oxidative phosphorylative enzymes. This study provides evidence that free ADP regulates mitochondrial respiration during hypercapnic acidosis and that acidosis does not inhibit the mitochondrial substrate regulation of respiration.

  • Research Products

    (12 results)

All Other

All Publications (12 results)

  • [Publications] Yoshioka,H.,Chance,B.,Papadopoulos,M.D.,et al,: "Observations of cerebral hemodynamics and oxygenation in sick neonates by near infrared spectroscopy." Brain Dysfunction. 4. 28-31 (1991)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Iino,S.,Yoshioka,H.,Osamura,T.,et al.: "Chronic cerebral lesions of mice following neonatal severe hemorrhagic hypoxic-ischmic encephalopathy." Brain Dysfunction. 4. 155-162 (1991)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 吉岡 博,Papadopoulos,M.D.,Younkin,D.P.,他: "胎児・新生児の脳障害予防のための病態解析.代謝動態" 脳と発達. 24. 159-163 (1992)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 吉岡 博,高屋 和志.沢田 淳他: "核磁気共鳴スペクトロスコピーによる新生児の脳代謝の評価" 周産期医学. 22. 1401-1405 (1992)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 吉岡 博.長谷川 功 松尾 泰孝他: "多ポイント法を用いた近赤外測光による新生児脳血液量の定量的測定の試み" 医学のあゆみ. (1993)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Hasegawa,K.,Yoshioka,H.,Sawada,T.,et al.: "Direct measurement of free radicals in the neonatal mouse brain subjected to hypoxia:an electron spin resonance spectroscopic study." Brain Research. (1993)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Yoshioka, H., Chance, B., Papadopoulos, M.D., Sawada, T.: "Observations of cerebral hemodynamics and oxygenation in sick neonates by near infrared spectroscopy." Brain Dysfunction.4. 28-31 (1991)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Iino, S., Yoshioka, H., Osamura, T., Goma, H., Okano, S., Sawata, T., Kusunoki, T.: "Chronic cerebral lesions of mice following neonatal severe hemorrhagic hypoxic-ischemic encephalopathy." Brain Dysfunction. 4. 155-162 (1991)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Yoshioka, H., Papadopoulos, M, D., Younkin, D. P., Chance, B., Mitsufuji, N., Sawada, T.: "Metabolic kinetics" No To Hattatsu (in Japanese). 24. 159-163 (1992)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Yoshioka, H., Takaya, K., Sawada, T., Naruse, S.: "Evaluation of brain metabolism in neonates by magnetic resonance spectroscopy." Perinatal Medicine (in Japanese). 22. 1401-1405 (1992)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Yoshioka, Hasewgawa, Matsuo, Y., Hirai, K., Kawase, S., Morioka, H., Sawada, T., Oono, Y., Hirao, K., Oka, K.: "Quantitative measurements of cerebral blood volume in neonates by near-infrared spectroscopy with multi-points method : a preliminary report." Igaku No Ayumi (in Japanese).

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Hasegawa, K., Yoshioka, H., Sawada, T., Nishikawa, H.: "Direct measurement of free radicals in the neonatal mouse brain subjected to hypoxia : an electron spin resonance spectroscopic study" Brain Research.

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

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Published: 1994-03-24  

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