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Biomedical subjects

S Yamanobe

Publications and source records attributed to S Yamanobe.

8 recordsLinked to original sources
PubMed1992

Three-component analysis of caloric nystagmus in humans.

Three-component analysis of caloric nystagmus, focusing on the horizontal, vertical, and torsional, using a computerized eye movement analysis system, was carried out in 10 normal human subjects. The caloric response was induced by cold stimulation to the right ear of the subjects in the supine and prone positions. In the supine position, the three components of nystagmus were toward the left (10 subjects), upward (eight subjects) or downward (two subjects), and clockwise (10 subjects). In the prone position, on the other hand, the three components were directed toward the right (10 subjects), downward (five subjects), upward (three subjects), and counterclockwise (10 subjects); there was no vertical direction in two subjects. These findings indicate that caloric stimulation activates the three semicircular canals simultaneously. Also the changes in the nystagmus direction in the supine and prone positions could be explained, at least partially, by the nonconvective component of caloric stimulation.

Adult↗
PubMed1992

Spontaneous remission in experimental autoimmune labyrinthitis.

We investigated the time course of hearing impairment and cellular infiltration into the inner ear after systemic sensitization of guinea pigs with a single intradermal injection of bovine inner ear antigen (IEAg) in complete Freund's adjuvant (CFA). Lymphocytes and polymorphonucleocytes appeared mainly in the scala tympani on days 7 to 14, and in addition there was thickening and cellular infiltration of the round window membrane at day 14. These cellular infiltrations resolved after day 28. The auditory brain stem response thresholds from IEAg-sensitized animals were significantly elevated after day 7. Some sensitized animals (n = 5) had spontaneous remissions after day 28; however, the hearing thresholds did not completely recover. These results demonstrate that experimental autoimmune labyrinthitis can be induced by a single inoculation of IEAg-CFA and that remission, as evidenced by clearing of the cochlear cellular infiltration and improved hearing thresholds, can occur spontaneously.

Animals↗
PubMed1991

Relationship between auditory brainstem response waveform and head size.

The relationship between the head size and the latency and amplitude of the auditory brainstem response (ABR) was investigated in 60 normal-hearing adults (30 males and 30 females). We found a strong positive correlation between the latency of ABR waves and the head size and a strong negative correlation surfaced between the ABR amplitude and head size. These results indicate that the head size is one of the most important factors influencing the waveform of the ABR.

Adolescent↗
PubMed1990

Eye movement analysis system using computerized image recognition.

A new technique for an eye movement analysis system utilizing infrared video recording and a computerized image recognition method is presented. The system consists of an infrared lighting apparatus, a very small infrared video charge-coupled device camera, a video tape recorder, an analogue-digital converter, and microcomputers. This system makes it possible to simultaneously analyze the slow-phase velocity quantitatively not only of the horizontal and vertical but also of the rotatory components of the energy-induced nystagmus. The maximum slow-phase velocity of the rotatory component of energy-induced nystagmus was found to be 4.1 degrees per second on an average in this study.

Adult↗
PubMed1990

Potentiation of inner ear damage following electron beam irradiation with CDDP administration.

This study was designed to examine the combined ototoxic effects of cisplatin, an antitumor platinum compound, administration and electron beam irradiation on the inner ear of guinea pigs, histopathologically. One group received saline solution 4 ml/kg/day and the other group received cisplatin of 2 mg/4 ml/kg/day for five consecutive days. The right temporal bones of all animals of both groups were exposed to the electron beam of 14 Gy/day 3 hours after the daily injection of saline or cisplatin. All animals were sacrificed for inner ear histopathological findings 21 days after the last injection. A combination of cisplatin administration and electron beam irradiation produced a severe potentiation of the outer hair cell damage with no inner hair cell damage. Therefore, in treatment of head and neck carcinomas, it is important to pay attention to inner ear damage caused by combination therapy of cisplatin and electron beam irradiation which involves the inner ear.

Animals↗
PubMed1989

[Auditory brainstem response in dead on arrival cases].

The relationship between ABR on the one hand and acid-base balance, EEG findings and prognosis on the other was studied in 47 cases of DOA. As for the acid-base balance, the balance tipped to acidosis in almost all cases. The ABR showed wave I to wave V in 25 cases, wave I to wave III in 2 cases and only wave I or no response in 20 cases on the admission day. The EEG was isoelectric in 27 out of 35 cases. All the patients who showed some activity in EEG had ABR which showed waves I through V. However, 11 of the 27 patients who were isoelectric EEG showed wave I through V potentials in ABR. By the relationship between EEG and ABR, the cases could be classified into 4 types, namely, 1) there are EEG activities with ABR showing up to wave V and the other types EEG are isoelectric with ABR findings that 2) wave V appears, 3) wave V disappears to leave wave I-III and 4) only I wave or becomes no response. The acid-base balance of the cases was inclined to acidosis; therefore, the effect of acidosis on ABR, EEG and disturbance of the brain tissue due to anoxic state wave suspected. Prognosis of DOA cases was poor and 87.2% died. All the patients who exhibited no response in ABR and isoelectric EEG at anytime of their course, died eventually. These findings suggest that combination of EEG and ABR enables one to learn more exactly the central function in those with disturbance of consciousness.

Acid-Base Equilibrium↗