Setsuko Morinaka

Effect of Experimental Acidosis on Nystagmus in Rabbits

Vertigo related to acidosis in Menieres disease has been reported. This study was undertaken to ascertain whether acidosis has any effect on vertigo. Since patients with Menieres disease usually show unilateral vestibular dysfunction, unilateral intratympanic injection of streptomycin sulfate (SM) was used to induce unilateral vestibular dysfunction in rabbits. Intratympanic SM injections induced vestibular destruction and elicited severe spontaneous nystagmus and ataxia. Then symptoms of acute vestibular upset gradually subsided and eventually disappeared completely. Three weeks after SM injections, in compensated rabbits, NH4Cl injection or CO2 inhalation was used to induce acidosis. Intravenous NH4Cl injection or CO2 inhalation induced nystagmus and ataxia again. In normal rabbits, no nystagmus was induced by NH4Cl injection or by CO2 inhalation. These results suggest that acidosis might be a cause of recurrence of vertigo in patients with unilateral vestibular dysfunction.

Use of Micro-Sliced Homograft Cartilage Plates in Tympanoplasty

We described our experiences in the use of micro-sliced septal cartilage homografts in tympanoplasty. The cartilage plates (0.1-0.5 mm thick) previously prepared with our method by use of a dermatome were used for the three purposes 1) to reconstruct the attic wall defect, 2) to prevent the retraction of the grafted fascia in myringoplasty, and 3) to prevent the displacement of the columella and the retraction of the grafted fascia in columella-type tympanoplasty. There have been no postoperative infections or extrusions in our 142 cases. These cartilage plates are considered to be very convenient in tympanoplasty.

The influence of daily electrical stimulation of the amygdala on optokinetic nystagmus in rabbits

To clarify the role of the amygdala in optokinetic nystagmus (OKN), the following experiment was carried out. Electrical stimulation, using 0.1-ms, 200-Hz pulse waves of 100 microA over a 30-s period, was performed once daily for 10 days to the amygdala of rabbits (medial or lateral area). Daily electrical stimulation of the medial area of the amygdala caused a significant increase of OKN frequency in rabbits.

Frequency of Autoimmune Chronic Thyroiditis in Outpatients of an Otorhinolaryngological Department

During the period between August and October 2002, there were 44 ambulatory patients with chronic autoimmune thyroiditis in our Otorhinolaryngological Department. The prevalence of chronic autoimmune thyroiditis was 6.8% of outpatients and the male/female ratio was 1:4.5. Chronic autoimmune thyroiditis was more frequent in patients aged 50-70 years. Among them, 20 patients were revealed to have normal thyroid function. Ten patients had hypothyroidism, 8 patients had subclinical hypothyroidism, one patient had thyrotoxicosis and 5 patients had subclinical thyrotoxicosis. Most patients had almost no symptoms related to thyroid function and thyroiditis was found by palpation of the thyroid gland. All 10 patients with hypothyroidism and 5 out of 8 patients with subclinical hypothyroidism were treated by thyroid hormone replacement therapy. Thyrotoxicosis and subclinical thyrotoxicosis were mild and transient, and no therapy was necessary for them.It is important to palpate the thyroid gland during examination of the neck, as chronic autoimmune thyroiditis is considered to be common. Therefore, it is important for general otorhinolaryngologists not to overlook thyroid diseases, and to palpate the thyroid glands routinely.

Spontaneous Disappearance of Adult Laryngeal Papillomas after Recurrence; A Case Report.

A 23 year-old male who complained of hoarseness was admitted to our hospital because of a laryngeal tumor. The tumor was removed by laryngomicrosurgery in February, 1996 and the histopathological diagnosis was laryngeal papilloma. One and a half months after removal, the tumor recurred at almost the same site and gradually increased to the size before removal in April, 1996. The laryngeal tumor was observed to have recurred in December, 1996, but then disappeared spontaneously and completely in January, 1997.Although the patient was not previously employed as a painter, he was engaged in the job of spray painting after the Hanshin earthquake (January 17, 1995). The onset of the complaint and the disappearance of the laryngeal tumor occured in accordance with the commencement and completion of his job as a painter, respectively. The role of the chemicals and papilloma virus in the development of laryngeal papilloma is discussed.