Japanese Journal of Medical Mycology

The experiences of otomycosis in Japan and Formosa for about forty years are summarised in this paper. The disease is common in Japan and Formosa with a tendency to increase in frequency from the north to the south. About fifteen hundreds strains obtained from patients with this disease were identified and nearly ninety per cent belonged to the genus Aspergillus. Among the aspergilli, A. terreus was most prevalent accounting for about seventy per cent. The pathogenicity of fungus was demonstrated by inoculation in the ear canals of rabbits and human volunteers. The best method of treatment of the disease was bathing of the ear canal with 0.02-0.1% phenyl mercuric acetate. Finally Polypaecilum insoltium, a new, scarcely known fungus, was introduced.

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The influence of betamethasone disodium phosphate was studied on cerebral infections of mice with 4 strains of Aspergillus fumigatus. Experimentally, the strains invade severely the kidneys of mouse but less the tissues of the brain. Male mice of dd line weighing 22±1g were used for the animal experiment. They were divided into 8 groups of 2 mice each. Two groups per one strain were employed and one group of them was received continuous 10 days' administration of betamethasone disodium phosphate, 2mg/day, intraperitoneally.
On the other hand, spore suspensions were prepared in 1/15M phosphate buffer (pH 7.4, supplemented with 0.01% tween 80) from 10 days cultures of the test strains on potato dextrose agar at room temperature. The number of spores was determined by the direct count with Thoma's hemocytometer chamber.
After 7 days' administration of the drug, each mouse was injected intravenously 5×10⁶ spores of the strain suspended in 0.2ml phosphate buffer solution. After 72 hours of injection, mice were sacrified and examined grossly and microscopically.
The extent of the growth of hyphae and cell infiltration of the brain was determined by the following method; after fixation with 10% formalin solution, the brain was cut from three directions (section A, B and C).
Section A was made by cutting horizontally along with the straight line that connects the olfactory brain and the upper part of the external ear hole. The section B was made from the cerebrum by cutting vertically and the section C was made from the cerebellum. Each section was stained with hematoxylineosin, periodic acid Schiff stain of Hotchkiss-McManus, luxol fast blue and cresylechtviolet.
By using micrometer, the areas of section A, B and C were measured (this was termed total area). The sum of areas showing the growth of hyphae and cell infiltration on the three sections was also measured. The ratio of that to the total area was calculated with the average data from 2 mice.
Grossly, no brain was swollen although a few hemorrhagic areas were found on the surface of the tissue. Microscopically, in all tissues of the brain small sporadic lesions that were composed of aggregates of leucocyte with a few hyphae were observed. Besides, necrotic foci, hemorrhagic areas, degeneration of nervous cells and demyelinization were observed. The extent of the growth of hyphae and cell infiltration in the brain was as follows; in the groups injected betamethasone disodium phosphate, the areas affected by the strain NICE was 1.92%, the strain A-F-7 1.69%, the strain A-F-8 0.76% and the strain K-11 0.13%, while, in the groups without administration, the strain NIGE 2.91%, the strain A-F-7 0.86%, the strain A-F-8 0.25% and the strain K-11 0.38%.
From the result, it seems to be considered that there is no definite influence of betamethasone disodium phosphate on the cerebral infection. However, mycotic lesions were established severer in the kidneys of mice injected betamethasone disodium phosphate than that not administered.

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