Hiroyuki Koshimo

Ciliary activity in the in vitro tubotympanum.

SummaryWe have introduced a tissue culture technique in which the ciliary activity of the cultured tubotympanum can be studied. We have found that ciliated cells of the eustachian tube and middle ear lining continued a beating activity during 168 h of observation. The mean loss of activity of the ciliated cells from the eustachian tube or mucosal sites proximal to the tube was 20% or less, while that of mucosal sites distal to the tube was about 40% even after 168 h of cultivation in our culture medium of RPMI 1640. Our technique of tissue culture is available for studying the long-term effects of various therapeutic agents or adverse factors on the ciliary activity in the tubotympanum.

Acute effects of irradiation on middle ear mucosa

Single field, fixed irradiation of bilateral tympanic cavities using 200-kV x-rays was administered to five guinea pigs. The irradiation dose was 30 Gy. They were killed immediately after irradiation, and bilateral middle ear mucosa was examined for ciliary activity and epithelial structure. Significant deterioration of the ciliary activity in the middle ear mucosa was observed, proximal as well as distal to the eustachian tube. Electron microscopy showed various changes in the irradiated middle ear mucosa. The most conspicuous findings were hyperreactivity in secretion, vacuolation of ciliated cells, and stomal edema.

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.

Ciliary activity on adenoids of patients with otitis media with effusion

Ciliary activity of the adenoidal surface in patients with otitis media with effusion (OME) was evaluated by a photoelectric method. Three groups of patients were compared: a non-OME group whose members had experienced no episode of OME; a middle ear effusion (MEE)-negative OME group whose members had an episode of recurrent OME but no MEE during the month preceding the operation; and an MEE-positive OME group whose members were experiencing an episode of recurrent OME with MEEs when tissue was taken for examination. To serve as a comparison, the ciliary activity in the central pharynx of normal guinea pigs was evaluated using the same technique. The ciliary activity in all patients was significantly lower than that in normal guinea pigs. No significant difference in ciliary activity was apparent between the non-OME group and the MEE-negative OME group. However, both were significantly higher than the ciliary activity of the MEE-positive OME patients. The following findings are drawn from our data: ciliary activity on the surface of hypertrophic adenoids is depressed, and patients with OME have reduced ciliary activity compared with those who have no otitis media or those who have otitis media without effusion.

Acute effects of sulfur dioxide exposure on the middle ear mucosa

A variety of atmospheric pollutants are known to depress mucociliary function in the respiratory system. Since the mucociliary function in the middle ear is similar, and the middle ear may be invaded by atmospheric pollutants, we decided to investigate the possible contribution of sulfur dioxide to middle ear effusion. Guinea pigs were exposed for 24 hours to 300 ppm of sulfur dioxide or air. Immediately after exposure, ciliary activity and epithelial structure were examined close to the tympanic orifice (proximal site) and more distal to it (distal site). In the animals exposed to sulfur dioxide, no effusion was found in the tympanic cavity. Ciliary activity was reduced only in the distal site. Electron microscopy demonstrated hypersecretion in the proximal site and severe pathologic changes in the distal site. Although the normally functioning cilia in the proximal site may prevent retention of surplus secretions in the ear, sulfur dioxide may promote middle ear effusion when combined with other detrimental factors, because it stimulates mucus secretion in the proximal site and impairs ciliary function in the distal site.

Effects of Bacterial Endotoxin on Ciliary Activity in the Tubotympanum

The discovery of endotoxin in effusion of otitis media with effusion (OME) has suggested the possibility that bacterial endotoxin may be involved in the pathogenesis and development of OME. In this study, we investigated the direct effects of lipopolysaccharide (LPS), possessing the major part of endotoxin activity, on the ciliary activity in the tubotympanum. The study shows that LPS deteriorates ciliary activity in a dose-response fashion and that even low levels can, with extended exposure, cause dysfunction of cilia. It can be postulated that endotoxin in middle ear effusions aggravates the condition of mucociliary dysfunction, thus leading to chronic OME.

Effects of irradiation on the ciliary activity of the eustachian tube and the middle ear mucosa

SummaryRadiation-induced changes in the ciliary activity of the eustachian tube and middle ear mucosa were investigated in a laboratory model. Twenty-four guinea pigs were sacrificed, and a mucosa at the bony portion of each eustachian tube and from the middle ear proximal and distal to the tube were sampled. The mucosal samples were irradiated with 200 kV hard X-rays discretely at a dosage level of 0.5–30.0 Gy, and the induced changes in ciliary activity were expressed as a percent deviation from baseline levels before irradiation. The present study demonstrates that the cilia of the eustachian tube and middle ear mucosa show different reactions to irradiation according to their tympanic locations.

Mucosal pathology of the eustachian tube after exposure to sulfur dioxide.

SummaryWe studied the mucosal pathology present in the eustachian tubes of guinea pigs following exposure to sulfur dioxide. Secretory sthenia but with slight deterioration of ciliary activity was observed in the mucosal samples examined. Our data have shown that 24-h exposure to 300 ppm sulfur dioxide does not cause otitis media with effusion in the guinea pig since active ciliary function will prevent any secretions produced from stagnating in the tympanic cavity.

Mucosal pathology of an experimental otitis media with effusion after X-ray irradiation.

Ten guinea pigs were irradiated with 30 Gy of x-radiation. Five were killed on the eighth day after irradiation, and the remainder were killed at the sixteenth day after irradiation. At the time of death, examination was made of the ciliary activity and the fine structure of the middle ear mucosa. Serous effusion was found in each tympanic cavity of all animals. It was shown also that the guinea pig, when irradiated with 30 Gy of x-radiation, exhibits pathologic abnormalities similar to those in humans with otitis media with effusion: degeneration of cilia or ciliated cells and changes in the vascular system (capillary injury and increased capillary permeability). Functional examinations showed that x-ray irradiation has delayed effects on ciliary activity, and the effects are much greater at the sixteenth day than at the eighth day. We speculate that the accumulation of effusion can be, at least partially, a consequence of ciliary dysfunction. The induction of sterile effusion by the use of x-ray irradiation provides a unique animal model for chronic otitis media with effusion of the serous type.

Effects of bacterial endotoxin on the ciliary activity in the in vitro eustachian tube

SummaryWe have used a tissue culture technique and a photoelectric method to examine the direct effect of lipopolysaccharide (LPS) on the ciliary activity present in the eustachian tube. Since LPS possesses the major part of the biological activity of endotoxin, our results show clearly that LPS deteriorates the ciliary activity in a dose-response fashion: LPS does not deteriorate the ciliary activity up to 168 h if its concentration is 1ng/ml or less; 10 ng/ml LPS can cause deterioration of the ciliary activity with extended exposure (more than 96 h); LPS can cause dysfunction of the cilia rather quickly if the concentration is 100 ng/ml or more. Our results show that the ciliary activity in the eustachian tube under clinical conditions can be affected by endotoxin.