Motoaki Kato

Mucociliary Disease of the Middle Ear during Experimental Otitis Media with Effusion Induced by Bacterial Endotoxin

Lipopolysaccharide (10 μg/mL) derived from Klebsiella pneumoniae was injected into the middle ear of guinea pigs. The animals were killed painlessly on days 1, 3, and 7 after inoculation, and the mucosal samples from two sites within the tympanic cavity, close to the tympanic orifice and distal to the orifice, were examined for ciliary activity and epithelial morphology. At day 1 and day 3 serous effusion was observed and deterioration of ciliary activity and morphologic changes were observed. No effusion was recognized at day 7, when the ciliary activity in the distal mucosa was still diminished and that in the proximal mucosa had recovered to a normal level. Our data have shown that lipopolysaccharide extracted from K pneumoniae can produce otitis media with effusion in laboratory animals, and dysfunction of cilia due to lipopolysaccharide probably is responsible for the accumulation of middle ear effusion. The mucociliary system is indeed an important defense system and failure of such a system, especially in the mucosa close to the tympanic orifice, can cause the buildup of effusions.

Functional Disorder of Eustachian Tube in Experimental Otitis Media with Effusion following Inoculation of Bacterial Endotoxin

A 10-μg/mL solution of lipopolysaccharide derived from Klebsiella pneumoniae was inoculated into the middle ears of guinea pigs. The animals were killed painlessly on the first, third, or seventh day after inoculation, and the mucosal samples from the bony portion of the eustachian tube were examined for ciliary activity and epithelial morphology. On the first and third days, when middle ear effusions were present, deterioration of ciliary activity and morphologic changes in the mucociliary system were observed. On the seventh day, when middle ear effusions were absent, the ciliary activity had recovered to normal. Our data show that endotoxin extracted from K pneumoniae can produce otitis media with effusion and that dysfunction of cilia caused by endotoxin is a factor responsible for the manifestation of otitis media.

Experimental otitis media with effusion induced by lipopolysaccharide from Klebsiella pneumoniae: Mucociliary pathology of the middle ear

We inoculated 100 micrograms/ml of lipopolysaccharide (LPS) from Klebsiella pneumoniae into the tympanic cavity of guinea pigs and examined the mucociliary pathology in the middle ear. Serous effusion was observed in the tympanic cavity of every animal on the first, third, and seventh day following the procedure, but the volume of the effusion had decreased to 0.2 ml on day 7. By that time, the ciliary activity in the opening to the eustachian tube within the middle ear had recovered to some extent, but in the middle ear distal to the opening no recovery was apparent. Our results show that cilia close to the eustachian tube play a more significant role in middle ear clearance than those in the middle ear distal to the tube. Compared with our previous study using 10 micron/ml of LPS, this study also demonstrates that inoculations with a higher concentration of LPS induces longer-term middle ear effusions.

RAST in Diagnosis and Therapy of Allergic Rhinitis

Skin tests, RAST, nasal provocation tests, and other nasal allergy examinations were performed on 463 patients exhibiting symptoms of allergic rhinitis who were examined at the Department of Otolaryngology of Osaka City University Medical School, and comparisons were made between the RAST scores and the results of the other examinations. A study was also made of the change in grade of the allergic rhinitis and the change of the RAST score resulting from one year of immunotherapy. The rates of agreement for patients with positive skin test and RAST were 60 to 70% for house dust (HD), house dust mites, Japanese cedar, and cocksfoot, and 10 to 35% for common ragweed and the fungus group. The RAST was positive for house dust 1, house dust 2, and Dermatophagoides farinae in 80 to 90% of the patients with house dust or house dust mite allergic rhinitis, and for over 80% of the patients with pollinosis (Japanese cedar or common ragweed). In most cases, the RAST scores were unchanged by one year of specific hyposensitization, and in the cases in which the RAST scores did change, the treatment was ineffective.

Electron Microscopic Study of the Inner Ear following Anaphylaxis

Although very little is known about the role of immunologic responses in disorders of the inner ear, including sensorineural hearing loss, data lending support to the possibility of their involvement have recently been published. The present experimental study was undertaken to obtain a better understanding of the fine structures of the inner ear following systemic immune responses. In guinea pigs sensitized with egg albumin, antigen challenge not only evoked bronchospasms, but also induced some pathologic changes in the inner ear, especially in the stria vascularis. These findings lead to the inference that the inner ear may be affected by systemic immune responses in sensitized animals.