Nobuhiro Okazaki

Experimental Otitis Media with Effusion following Middle Ear Inoculation of Nonviable H Influenzae

In order to test the hypothesis that nonviable bacteria can induce middle ear inflammation leading to persistent middle ear effusion (MEE), we conducted an animal experiment using formalin-killed Hemophilus influenzae, the bacterium reported to be the most common pathogen isolated from chronic MEEs. Over 70% of the chinchillas injected with formalin-killed H influenzae type b or a nontypeable isolate developed sterile, straw-colored serous MEEs, and exhibited histological evidence of extensive inflammatory changes of the middle ear mucosal connective tissue and epithelium. Control animals injected with pyrogen-free sterile saline did not exhibit any inflammatory changes or effusions in the middle ears. Our data suggest that endotoxin on the surface of H influenzae, a gram-negative bacterium, may be responsible for the induction of the otitis media with effusion. It is suggested that endotoxin (even when the organisms are no longer viable) may be responsible for the production of serous MEE and inflammatory changes in the middle ear.

Experimental Study of the Eustachian Tube Function with Regard to its Related Muscles

Utilizing electromyography and electrical muscle stimulation, the muscle responsible for opening the Eustachian tube was examined im 12 dogs. Different time values for tubal opening and levator activity indicate little contribution of the levator in the functioning of the tube. By relatively low stimulation of the tensor, the tube opened consistently, while the levator failed to produce any dilation of the tube, regardless of the amount of stimulation, in 6 dogs. Thus, it is concluded that the sole muscle responsible for tubal opening is the tensor, while the levator does not participate in the functioning of the tube.

Experimental otitis media with effusion induced by nonviable hemophilus influenzae: cytologic and histologic study

In an earlier study the authors demonstrated that formalin-killed Hemophilus influenzae induces serous-type middle ear effusion in chinchillas and provides an excellent model for the study of human otitis media with effusion. The present study was initiated to evaluate the morphologic and histologic changes that occur in the middle ear after injection of this organism. All of the experimental animals injected with formalin-killed H. influenzae in the present study had straw-colored serous-type effusions within four days after injection. The submucosal thickness, mononuclear cell density, and capillary permeability all increased dramatically in the experimental animals. Marked bleeding, tissue edema, and cellular infiltration in the submucosa were prominent findings after injection of the inactivated bacteria. Half of the experimental animals had histologic evidence of marked proliferation of epithelial cells resembling adhesive otitis media. These findings suggest that nonviable H. influenzae are capable of inducing severe inflammatory changes in the middle ear and may play an important role in the pathogenesis of otitis media with effusion and its sequelae.

Experimental Study of the Pumping Function of the Eustachian Tube

To determine the muscle responsible for the pumping function of the Eustachian tube and to examine the detailed processes of this function, we conducted (1) a measurement of tympanal pressure during swallowing and during selective stimulation of the tensor and the levator muscles, and (2) visual and radiographic observation of fluid in the tube; in cats, dogs and a monkey. the results were: (1) formation of negative pressure in the tube by contraction of the tensor muscle; and (2) displacement of the fluid from the tympanum to the pharynx through the tube by repeated contractions of the tensor. It was concluded that contractions and relaxations of the tensor muscle cause the pumping function of the tube, which expells any fluid from there into the pharynx.

Cineroentgenographic and electromyographic studies of Eustachian tube function

ZusammenfassungZur Feststellung des Öffnungs- und Schließungsvorganges der Tube während des Schluckens wurden an drei Affen simultan das Röntgenkinematogramm und das Elektromyogramm registriert. Dabei zeigte sich, daß sich die knorpelige Tube synchron zur Aktivität des M. tensor veli palatini für ca. 250 ms durch eine Bewegung der lateralen Wand nach außen öffnet. Daneben erweitert sich die pharyngeale Tubenöffnung für eine relativ lange Zeit synchron mit der Aktivität des M. levator veli palatini. Diese Zeitverzögerung zwischen den beiden Tubenabschnitten scheint die Pumpfunktion der Tube zu unterstützen.SummaryTo determine the opening and closing process of the Eustachian tube during swallowing, the simultaneous recording of cineroentgenograms and electromyograms (EMG) was carried out in three monkeys. It was revealed that synchronous with the activity of the tensor veli palatini muscle, the cartilaginous tube opened for a very short time (ca. 250 ms) by an outward movement of its lateral wall. On the other hand, the pharyngeal orifice of the tube dilated for a relatively long time synchronous with the activity of the levator veli palatini muscle. These time lags between two parts of the tube seemed to help the pumping function of the tube.

Role of the Tensor Veli Palatini Muscle in Movement of the Soft Palate

To examine the role of the tensor veli palatini muscle in palatal movement, we conducted 1) quantitative measurement of palatal movement by selective stimulation of the tensor and levator muscles, and 2) EMG recording of the two muscles during phonation. The results were: 1) negligible palatal movement upon tensor stimulation, despite a marked velar elevation by levator stimulation; and 2) little EMG activity of the tensor and marked EMG activity of the levator during phonation. It was concluded that the tensor plays no role in the palatal function.

Selective Induction of Macrophages in the Middle Ear

A method is described for inducing an influx primarily of macrophages into the middle ears of chinchillas using keyhole limpet hemocyanin (KLH, a strong immunogen) and mineral oil (a nonimmunogen) to provide adequate numbers of these cells for study. Although KLH and mineral oil both induced sterile otitis media in which macrophages were the predominant cell type present in the middle ear, the cytological and histological responses of the middle ears to these substances differed. KLH proved to be a much stronger inducer of actively phagocytic macrophages and also produced serous effusions in about 11% of the experimental animals. This experimental model provides an opportunity for the in vitro and in vivo study of the role of macrophages, the predominant cell type associated with human chronic otitis media with effusion, in the defense system of the middle ear.

Significance of Levator Muscle Sling Formation in Cleft Palate Surgery: Evaluation by Electrical Stimulation

The effect of levator muscle sling formation in cleft palate surgery was evaluated by electrical stimulation of the muscle at surgery. Palatal movement before and after sling formation was recorded through a force transducer. After muscle sling formation, the soft palate was elevated more effectively toward the retropharynx and its mobility increased remarkably. The surgical procedure, which had been proposed on the basis of anatomic considerations, was proved to be effective for improving velopharyngeal function.

Acoustic analysis of the inflation sound in Eustachian catheterization.

ZusammenfassungZur Prüfung der Zuverlässigkeit des Katheterismus der Ohrtrompete als Test einer Tubenfunktionsstörung wurde an 130 Tuben eine sonagraphische Analyse des Einblasegeräusches durchgeführt. Dabei zeigten für den jeweiligen Funktionszustand objektive Untersuchungsmethoden und Sonagraphie praktisch identische Resultate. Weiter konnte mittels eines Tubenmodells gezeigt werden, daß der Ton bei der Tubenstenose vorwiegend durch Luftwirbel am pharyngealen Tubenostium entsteht.SummaryTo check the reliability of the Eustachian tube catheterization as a test of tubal dysfunction, a soundspectrographic analysis of inflation sound was carried out in 130 tubes. A close correlation between each tubal condition classified by objective tests and their soundspectrographic features indicated the reliability of the test. The origin of an inflation sound in obstructive tubes which displayed three sonagraphic types was examined by a tubal model. It was revealed that the stenotic sound mainly originated from turbulent air at the tubal orifice.

Radiographic Observation of Opening Mechanism of the Eustachian Tube

耳管開大機構の詳細, 特に耳管筋と耳管開大運動との関係を知る目的で, 日本ザル4頭を用い, 口蓋帆張筋, 挙筋電気刺激時の耳管造影レ線映画撮影および連続レ線写を行った. その結果, 挙筋収縮では耳管隆起 (後唇) の後方運動により耳管咽頭口は拡がるが, 耳管自身は全く開かない事, これに反し張筋収縮では軟骨部耳管が全長にわたり開き, これは耳管外壁の前外方への拡張による事が明らかとなった.