Grant-in-Aid for Scientific Research (A)
|Allocation Type||Single-year Grants|
Biomedical engineering/Biological material science
|Research Institution||UNIVERSITY OF TOKYO|
KAGA Kimitaka University of Tokyo, Dept. of Otolaryngology, Professor, 医学部・附属病院, 教授 (80082238)
NAKAMURA Masaichi University of Tokyo, Dept. of Otolaryngology, Assistant, 医学部・附属病院, 助手 (90217894)
MUROFUSHI Toshihisa University of Tokyo, Dept. of Otolaryngology, Lecturer, 医学部・附属病院, 講師 (30242176)
YAMASOBA Tetsuya University of Tokyo, Dept. of Otolaryngology, Lecturer, 医学部・附属病院, 講師 (60251302)
太田 康 東京大学, 医学部(病), 助手 (40251285)
|Project Period (FY)
1993 – 1996
Completed(Fiscal Year 1996)
|Budget Amount *help
¥4,300,000 (Direct Cost : ¥4,300,000)
Fiscal Year 1996 : ¥500,000 (Direct Cost : ¥500,000)
Fiscal Year 1995 : ¥800,000 (Direct Cost : ¥800,000)
Fiscal Year 1994 : ¥3,000,000 (Direct Cost : ¥3,000,000)
|Keywords||Auditory brainstem responses / Brain daeath / Temporal bone pathology / Neuropathology / Red cell / Carotid artery / Basilar artery / Corti's organ / 側頭骨病理 / 蝸牛神経核 / 神経病理 / 脳血管障害 / 無酸素状態|
Since auditory brainstem response (ABR) was discovered by D.L.Jewett in 1970, it has been widely used in the NICU or ICU as the most important tool for making a diagnosis of coma and brainstem death. In the state of brain death, the configuration of ABR shows wave I only or no response. However, the pathological study corresponding to such ABR abnormalities has rarely reported. Then, reliability of ABR for the diagnosis will be higher if pathological evidence is collected. In order to compare ABRs with temporal bone pathology and neuropathology, we designed clinical and pathological studies and animal experiments.
Research results are discribed as follows.
I.Clinical study :
1) When ABRs of patients showed wave I only or no response because of brain death, the temporal bone pathology demonstrated mostly destruction of corti's organ and exceptionally normal corti's organ. Meantime, the neuropathology revealed that red cells in the vessels in the brainstem were ghost like cells without hemo
globin but those in the basillar artery and its branches on the brainstem were normal. This discrepancy means that the blood flow in vessels in the brainstem is shut down but on the arteries on the brainstem is normal in spite of brain death.
2) The neuropathological study revealed entire decrease or disappearance of neurons in the cortical layr of the cerebelium and cerebrum but preservation neurons of brainstem auditory nuclei except cochlear nucleus.
Rats experiments were conducted as various models of coma and brain death. 1) Occlusion of bilateral carotid arteries did not change ABR configuration. 2) Occlusin of the basilar artery showed complete disappearance of ABR.
3) Total spiral anesthesia which was made by injection of lidocaine into subarachnoidal space revealed disappearance of ABR.ABR disappeared a couple of minutes after injection but recovered normally within an hour. Moreover, ABR's origin was demonstrated by whole brainstem field potentials analysis in cats. Less