| Project/Area Number |
09670351
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Hygiene
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| Research Institution | Department of Hygiene, Asahikawa Medical College |
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Principal Investigator |
YAMAMURA K. Asahikawa Medical College Hygiene, Professor, 医学部, 教授 (80109959)
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| Co-Investigator(Kenkyū-buntansha) |
ITOH T. Asahikawa Medical College Hygiene, Assistant, 医学部, 助手 (20271760)
堀田 秀一郎 旭川医科大学, 医学部, 助手 (30271761)
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| Project Period (FY) |
1997 – 1998
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| Project Status |
Completed (Fiscal Year 1998)
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| Budget Amount *help |
¥2,500,000 (Direct Cost: ¥2,500,000)
Fiscal Year 1998: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1997: ¥1,800,000 (Direct Cost: ¥1,800,000)
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| Keywords | Damage-risk criterion (DRC) / Impact tone / CM / CAP / EP / K^+ ion / Leq_<24h> / Na^+ ion / Damage-risk criterion(DRC) / damage-risk criterion(DRC) / 断続音 / (CM) / (CAP) / (EP) / L_<eq24h> |
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| Research Abstract |
The purpose of this study, using guinea pigs, exposed to impact tone was to test the adequacy of Leq_<24th> for estimating the changes in electrophysiological data namely, endocochlear potential (EP) and the change in K^+ion and Na^+ion in concentration the endolymph. The temporal pattern of tone was 1pulse/1sec. The former tone had a Leq_<24th>=95, 90, and 85dB and the latter impact tone had a Leq_<24th>=95dB.The results are the following. Both steady state and impact tone exposure causes change of electrophysiological data. The negative EP induced by impact tone exposures was influenced the following way. The rate of pulses/s is as important factor at impact tone exposure. Having more frequent pulses (1pulse/1sec versus to 1pulse/3sec) results in more inhibition, namely, the former condition of impact tone exposure caused smaller absolute value of negative EP than that of latter conditions. Impact tone exposure (1pulse/s) having Leq_<24th>=95dB, showed equal negative EP at the steady state tone of 100dB.Also, latency of EP showed the same tendency as the negative EP.The K^+ concentration time course in the endolymph remained similar to the control (Exp. 1) only when the Leq_<24th> was low (85dB).The Na^+ion concentration time course was influenced the same way was K^+ion time course, suggesting that K^+ion and Na^+ion movement is altered by tone exposure and the same Leq does no show same changes. We conclude for our recent experiments of impact tone that Leq_<24th> is not an accurate DRC (damage risk criteria).
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