The histopathological findings of the temporal bones from two cases with DIC were described. Although hemorrhage in the inner ear was found in the both cases, otological findings were different between the two. Case 1 was a 19-year-old woman with angiosarcoma of the mammary gland. Hemorrhage was observed in the mesotympanum, as well as in the scala tympani and spiral ligament of the basal turn of the cochlea. Tumor cell infiltration was observed in various sites of the middle ear such as around the facial nerve. She, however, had no otological complaint except for slight dizziness. Case 2 was a 46-year-old man with acute myelofibrosis. Severe hemorrhage was observed in the internal auditory canal, the cochlear duct and the saccule. The organ of Corti showed extensive degenration. He had complained of bilateral deafness.

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The serial sections of the statocysts of the four kinds of the phylum mollusca, class cephalopoda, order decapoda, were observed with the 10% formalin diluted with seawater as soon as possible after being fished with a line. They were dehydrated with etylalcohol diluted with distiled water and seawater, then embedded in celloidin. The sections were cut 30μm and stained with hematoxylin and eosin.
As a result of this method, the macula statica, crista statica, processes, statolith, macula and crista nerves were observed.

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It is well known that the artifacts are easily produced by those chemicals in the process of exposing otolithes by SEM. Instead the use of the usual method of fixation by glutaraldehyde and dehydration by alchohol, tried with freezed dry method with saccular otolithic membrane of guinea pigs, and obtained the results:
1. The surface of each otolith is smooth without fissure and the tridimensions on both sides are clear.
2. Otolithic layer punched out, so the underlying gelatine layer are exposed here and there.
3. Those otolithes remained after manipulation are linked in irregular hexagonal arrangement.

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Guinea pig utricular maculae were irradiated by Argon laser (1.0W × 1.0s, spot size 100 μm) through the oval window under an operating microscope without touching the perilymph. The stapes was replaced at the oval window after irradiation. The inner ear was studied morphologically and physiologically. Immediately after the irradiation, hair cells, supporting cells, and nerve fibers of the utricular macula disappeared in a shot area of 100 μm in diameter. The otolith remained unchanged.
Seven weeks after the irradiation, the utricular macula with the nerve fiber had completely disappeared. Other parts of the inner ear were morphologically unchanged. The compound action potential indicated normal cochlear function.

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We have demonstrated that changes in mean arterial blood pressure (MABP) are accompanied by changes in systemic oxygen tension, carbondioxide tension, and other parameters in the circulating blood. For this reason the cochlear blood flow does not fully represent the level of cochlear oxygenation. Differential coefficient studies of the simultaneous measures of cochlear and muscular blood flow (laser Doppler flowmeters), cochlear and systemic oxygen tension (polarography), and MABP revealed that 1) oxygen supply to the cochlea has slightly positive correlation with MABP, while the cochlear oxygen consumption is kept constant.

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The linearity of the output signal of a laser Doppler flowmeter through the cochlear bone was investigated by model study. The model consisted of a highly diffused plate, a bundle of hollow fibers, a lateral bony wall of the cochlea of the guinea pig. The lateral bony wall was placed on the bundle of hollow fibers. The diluted heparinized blood was infused into the bundle of hollow fibers at predetermined flow rates. The flow was measured through the bony wall with the laser Doppler flowmeter (PF2, Perimed, Sweden). The results showed the output signal was proportional to the product of the blood velocity and hematocrit (r=0.97). However, the magnitude of output signal was obviously attenuated comparing with the direct measurement.

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Simultaneous measurements of Hemodynamics and oxygen sufficiency were made in the guinea pig cochlea, brain stem surface and skin by reflectance spectrophotometry, which provides the indexes of hemoglobin concentration (IHb) and oxygen saturation (ISO₂). Cochlear IHb generally followed brain stem IHb. But skin IHb showed different change with intravenous administration of Angiotensin II which raised cochlear and brain stem IHb and dropped skin IHb. Similar pattern of ISO₂ change were obtained in these three area, however, the degree of ISO₂ change appeared lower in the brain stem surface. Results obtained suggest that cochlear hemodynamics is more analogous to the brain stem surface than that of the skin but oxygen reserve in the cochlea is not as much as that in the brain stem surface.

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Simultaneous measurement of cochlear hemodynamics by reflectance spectrophotometry and laser doppler flowmetry were made in the guinea pig. The former technique provides the index of local hemoglobin concentration (IHb) and the index of oxygen saturation (ISO₂). Changes of IHb, ISO₂, and blood flow (BF) by laser doppler flowmetry were studied with several manipulations. IHb and ISO₂, generally followed BF but they showed independent changes under the certain conditions: general cooling which raised IHb and dropped ISO₂, and BF suggesting ischemia with congestion; hemodilution which dropped IHb and raised BF suggesting increased velocity. Combination of these two technique appears to be useful for the better understanding of cochlear hemodynamics.

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Using guinea pigs, systemic blood pressure, cochlear blood flow and perilymphatic Po2 were recorded simultaneously, during Glycerol infusion. To make comparison between Glycerol and Furosemide, same experiment was performed on Furosemide. By intravenous injection of 40% Glycerol (2ml/kg), cochlear blood flow increased more rapidly than systemic blood pressure and perilymphatic Po2.
After the administration of Furosemide (10mg/kg), a slow decrease of systemic blood pressure occurred with paralleled changes of cochlear blood flow and perilymphatic Po2. These decrease o f cochlear blood flow and perilymphatic Po2 were considered to be dependent on the systemic blood pressure changes, indicating the evident difference between Glycerol and Furosemide in the effect on cochlear blood flow and perilymphatic Po2.

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The cochlear blood flow was investigated with laser Doppler method in 24 ears of the guinea pig before, during and after the administration of the steroid hormone. Any meaningful change in cochlear blood flow was not observed 20 minutes after the intravenous administration of the steroid hormone. In addition, even the large amount of steroid hormone did not affect the change in cochlear blood flow induced by the asphyxia.

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The cochlear blood flow in the apical turn and in the basal turn were simultaneously measured in 12 ears of the guinea pig with the laser Doppler method before, during and after the asphyxia. The duration of asphyxia were 2.5minutes, 5minutes and 7.5minutes, respectively. The change in cochlear blood flow after the asphyxia did not show any meaningful differences in both turns, which could be the reflection of the change in the systemic blood pressure. However, the change in the apical turn could be slightly more prominent than that in the basal turn.

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Cochlear blood flow changes in the hypotensive state using Trimetaphan Camsilate were observed by a laser doppler flowmeter. In these hypotensive conditions, cochlear blood flow showed concomitant changes with those of systemic blood pressure in a higher correlation. This fact may indicate that the system of cohlear blood flow has a passive aspect in the condition of blood pressure change.

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Laser doppler flowmetry was used to study the effect of increased intracranial pressure on cochlear blood flow (CBF) in guinea pigs. Endocochlear potential (EP) and endolymphatic pressure were measured simultaneously with a servo-controlled micropipet system. Endolymphatic pressure increased with little or no time lag as the intracranial pressure rose. When the intracranial pressure rose above a critical point, the CBF decreased suddenly and a little later EP started going down gradually. These changes were completely reversible upon release of intracranial pressure. We conclude that increased intracranial pressure causes an impediment in the circulation of cochlea.

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The effect of elevation of inner ear pressure on cochlear blood flow was studied using non-radioactive microspheres and laser doppler flowmeter in guinea pigs. Due to the injection of saline through a glass capillary tube inserted into the scala tympani, the inner ear pressure was raised. The elevation of the inner ear pressure caused significant reduction of cochlear blood flow except to the modiolus. Above all, blood flow in the capillaries or microcirculation in the cochlea was most easily impaired by the elevation of the inner ear pressure.

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The effect of local anoxia (1 hour) upon EP under hypothermic condition (28°C) was observed in 4 albino guiner pigs and the results were compared with those of control animals (37°C, n: 5). The levels of the EP recorded before local anoxia were 84.5mV and 85.5mV at 28°C and 37°C, respectivery. On termination of local anoxia, the EP rapidly increased and reached a certain static level in 30 minutes, i. e. 60.7mV and 49.4mV at 28°C and 37°C, respectivery.
The present results indicate that the reduction of metabolism due to hypothermia protects the damage of the cells in the stria vascularis, resulting in the higher recovery level of the EP after transient local anoxia.

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A calcium channel blocker, nifedipine was applied to cochlea by perilymphatic perfusion. EP decreased gradually after perfusion wiht the nifedipine solutions when the concentration was higher 100ng/ml. At a concentration of 200ng/ml, EP decreased from+70mV to 14mV. At 1000ng/ml, it decreased from+70mV to +54mV and stayed at this level during perfusion. From these results, it is considered that calcium influx to stria vascularis plays a role in maintaining EP. There are three possible explanations for the influence of nifedipine on EP. The most likely explanation for the decrease in EP is that through Na-Ca exchanges, a fall in the intracellular Na concentration inhibits the Na-K pump or K pump. The second explanation is related to cAMP and the third involves diffusion potential.

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We had reported the change of endocochlear dc potential (EP) on normal guinea pigs which were breathed 5%O₂+95%N₂ gas or 2.5%O₂+97.5%N₂ gas. The EP decreased rapidly and then increased Slowly. The time course of the EP is dependent on the functions of stria vascularis and hair cells. In this report, we studied the change of EP on the kanamycin sulfate (KM) administrated guinea pigs which were breathed 5%O₂+95%N₂ gas or 2.5%O₂+97.5%N₂ gas. On the KM administrated guinea pigs, the EP also decreased rapidly and then increased slowly. The reaction of that was later than that of normal. The reduction of EP of that was smaller than that of normal. It is suggested that stria vascularis have the function stabilized EP in 80-90mV.

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Endolymphatic hydrops was surgically induced in the left ears of albino guinea pigs. In the 6th, 12th, and 24th postoperative weeks, cochlear endolymphatic potential (CEP) was measured through the round window. The averages of CEP in each postoperative period after one month were found to be lower than normal controls by 20mV or more. Maximal values of CEP reduction after Furosemide injection (50mg/kgBW) in hydropic ears were greater than those in normal controls. After maximal reduction CEP rapidly recovered to the original level in normal controls and hydropic ears in the 6th postoperative week. Recovery rate was slower in the 12th week animals, and CEP never reached the original level in the 24th. Consequently, CEP susceptibility to Furosemide is considered to correspond to the morphological changes of stria vascularis in hydropic ears.

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The resting potentials, K⁺ and Na⁺ activities were recorded from the cells the stria vascularis, using an approach developed for the intracellular recording. The mean±S. D. of the resistance of the microelectrode (3MKCl) was 52.6±20.6 and 46.3±18.7megohm (N=6) before and after the penetration of the stria vascularis. The tip diameter was estimated less than 0.1μm and less than 0.5μm in the 3MKCl electrode and the ion-sensitive double barreled electrode respectively. The resting potentials of the cells of stria vascularis increased by positive steps during penetration. The K⁺ was increased but the Na⁺ was decreased during the penetration of the stria vascularis. The K⁺ and Na⁺ activities in the scala media were 131.5±21.5mEg/L (N=16) and 1.8±1.5mEg/L (N=20) respectively.

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The inhibitory response of the posterior semicircular canal (p. s. c.) ampullary nerve was studied in comparison with the excitatory response. The isolated p. s. c. of the bull frog was stimulated by mechanical endolymphatic flow toward either ampullofugal (AF, excitatory) or ampullopetal (AP, inhibitory) direction. When the same amount of stimulus was given, the magnitude of the excitatory and inhibitory responses were equal regardless of the initial position of the cupula. The inhibitory response yielded a time constant approximately 3 time as long as the excitatory response. AF stimulus immediately followed the AP stimulus gave rise to a distinct positive DC potential, although action potential could hardly be evoked. It should be further studied whether or not this positive DC potential reflects a receptor potential.

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The effect of furosemide and canrenoate, aldosterone antagonist upon the DC potential in the endolymphatic sac (ESP) was examined in the guinea pig. Furosemide produced no change in the ESP. Canrenoate decreased the ESP, whereas it produced no change in the endocochlear potential (EP). The change in the ESP induced by canrenoate was dose-dependent. The results suggest that the the mechanism underlying the ESP is different from that of the of the EP.

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We report here the first evidence that ATP depolarizes the outer hair cells isolated from guinea-pig cochlea and activates a large cation channel. The outer hair cells were dissociated mechanically after enzyme treatment. Drugs were applied by a rapid concentration-jump technique. The ATP-gated channel was permeable for both mono and divalent cations. The relative permeability was in the order of Ca²⁺> > Li⁺> Na⁺> Cs⁺> > choline⁺. The potency of ATP agonists was ATP> > ADP> AMP-PNP> α, β-methylene ATP=β, γ-methylene ATP, indicating that the ATP-gated channel is a large cation channel and is classified as P2 subtype of the purinergic receptor.

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The cytoplasmic free Ca²⁺ concentration ([Ca²⁺] i) plays a key role in the mechano-electrical transduction of hair cells. The relationship of depolarization to the [Ca²⁺] i of single hair cells was monitored by digital imaging microscopy using Ca²⁺-sensitive dye fura-2. Both membrane depolarization, induced by elevated K⁺ in the extracellular fluid, and mechanical stimulation of the hair bundle, led to an increase in [Ca²⁺] i.

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Although the only direct connection between scala vestibuli (SV) and scala tympani (ST) appears to be the helicotrema, there is also a radial communication route, predominantly through the spiral ligament since this tissue has a loose fibrous structure. In this study, a non-toxic ionic tracer, trimethylphenylammonium (TMPA) was introduced to the one scala perfusion experiment to evaluate the coupling between SV and ST in the guinea pig cochlea. A microelectrode in the 3rd turn perilymphatic space of the non-perfused scala detected a rapid increase of the tracer concentration during perfusion. It is concluded that the radial coupling between SV and ST allows the rapid diffusion of small solutes so the two compartments cannot be considered as independent.

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Integration of chip coil to the extracochlear implants reduce the size of the implant, but the functional characteristics of the coil is not well understood yet.
We tested the chip coil on the guinea pigs and found that it effectively transmitted the output of speech processor to the cochlea. The compound action potentials recorded from auditory nerve of the guinea pigs was almost similar in amplitude and latency to those obtained using system without chip coil.
The chip coil may transmit the stimuli as effective as the transmission system without chip coil.

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The relation between stimulating time duration and loudness level by loudness balance method in Bekesy Audiometry was studied in 7 normal hearing subjects. We used a total of 9 types of signals varying in time duration. The results were as follows.
1. The loudness balance levels increased, as the stimulating time duration increased for 1000 msec period. The change in loudness in proportion to time duration was systematic.
2. There was no significant relation for the longer periods than 1000 msec, the loudness levels were almost constant.
3. We speculated from the data that the temporal window was almost the time duration of 1000 msec.

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A simple method of inducing caloric nystagmus in the rabbit was devised. The animal with black eyes is positioned on its back with the neck ventriflexed 90 degrees in order to bring the horizontal semicircular canal into the vertical plane. Eight cc of cubical ice at 0°C is then placed on the skin posterior to the external auditory meatus, so as to allow the ice to cool the ipsilateral temporal bone for approximately four minutes. Nystagmus directed to the opposite side was consistently eveloped about 2 minutes after the start of the stimulation, and easily recorded by electronystagmography without any special instrument for fixation.

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Specific body responses (heart rates, CV of R-R, adrenaline and free fatty acids) to direction (X: longitudinal, Y: transverse, Z: vertical) and frequency (0.14Hz, 0.29Hz) of the linear oscillatory stimulation and to sensory conflict conditions (linear oscillatory stimulation vs visual stimulation) were investigated in four adult rabbits. The main results were as follows: 1) The linear oscillatory stimulation in direction X diminished heart rates and increased the activities of both sympathetic and parasympathetic nerve systems; 2) Thresholds of the body responses to the linear oscillatory stimulation increased in the order of directions Z, X, Y; 3) Compared to independent stimulation in direction X, sensory conflict condition paired with visual stimulation increased heart rates and activity of the sympathetic nerve system, but diminished activity of the parasympathetic nerve system.

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The influence of external auditory canal pressure on vestibular nerve activity was studied using guinea pigs. More than 30% of the neurons in the Scarpa's ganglion responded to the changes in the external auditory canal pressure. Most of those responsive neurons decreased their firing rates when positive pressure was applied, while they generally increased their firings when negative pressure was applied. Two out of three units in the guinea pigs whose endolymphatic duct was occluded increased their firings when positive pressure was applied.

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Endoscopic observation of inner surface of the eustachian tube, using a newly developed very thin fiber optical system (∅=0.6mm) for ear-nose-throat were reported. Transnasal introduction of the scope into the eustachian tube was performed via a inflation catheter or a biopsy-channel of a ENT-fiberscope. To visualize the cartilaginous portion of the eustachian tube, the pneumatic endoscopic procedure was needed in order to avoid a contact of the tip of the thin fiberscope to the mucosa.

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We focused on the eustachian tube of the Ginea pig (which is functionally a patulous eustachian tube also called a safty tube) and then studied ventilation of the tympanic bulla. The tympanic bulla revealed a low PO₂ tension of approximately 40 mmHg which was affected by the respiratory gases. Scanning electron micrograph showed that capillary structure from the bone wall were divided into a relatively small number of the branches and that many branched arteries and veins formed vessel plexuses with active metabolism just under the mucous epithelium. These observation showed that thus the gas metabilism being closely related to ventilation of the human middle ear cavity and submucousal capillary structure in the tympanic bulla are supposed to extremely related to the gas metabolism.

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The change of the ciliary activity in the tubotympanum during in an in vitro allergic reaction has been examined. The tubotympanic mucosa was sampled from healthy guinea pigs, and it was placed in a chamber filled with 1 ml of RPMI 1640 and human blood. When 10μg of antigen protein was introduced in the medium, the ciliary activity was enhanced 10-50 minutes postinjection of the antigen. However, the cilium from the distal mucosa from the tube showed dysfunction after the enhancement. The degree of the change related with the percent histamine release.

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DF-100 (Puri Dyne, Inc., N. C., USA) is a natural substance extracted from seeds of grapefruits, which has been reported to have antimicrobial activities such as antifungal, antibacterial and antiviral activities. DF-100 has been thought to have a possibility of usefulness in cases of various infections because of its low irritability to tissues. In this paper, DF-100 was tested for the toxicity on the mucosa of the eustachian tube of guinea pigs. DF-100 was also tested for its antimicrobial activity by measuring its MIC against Candida, S. aureus (MRSA) and Pseudomonas sp. DF-100 induced significant ciliary inhibition at concentrations higher than 500ppm, whereas 5Oppm of DF-100 induced mild ciliary inhibition, which recovered following irrigation with Krebs Henseleit buffer. MIC of DF-100 against Candida sp. was less than 100ppm. Its MICs against Pseudomonas aeruginosa and Ps. cepacia were more than 3, 600ppm whereas 3.15ppm against S. aureus (MRSA).

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Until now endotoxin has been identified as possibly playing a role as a pathogenesis of otitis media with effusion. Of paticular interest, is the inhibition of endotoxin induced biological responses by specific PAF antagonists, which has been perviously reported suggesting involvement of PAF in endotoxin induced biological responses. In the present study, PAF induced mucosal damage of the eustachian tubes of guinea pigs was described. The surface profile of the mucosal specimens, which were aseptically obtained under an operating microscope, were observed in Eagle's MEM under a phase-contrast microscope equipped with a thermoregurated humidified CO₂ chamber. The profile was monitored on a TV monitermagnified 2, 500x and simulteniously recorded on videotapes. Ciliary activity was photoelectrically measured on the TV moniter. PAF induced ciliary inhibition along with swollen epithelial cells, exfoliation of the cells and eventually ciliostasis at concentrations of 10^-6M to 10^-10M. In contrast, both of the control groups of methanol and 10^-6M lyso-PAF in Eagle's MEM control groups failed to induce any alterations of the mucosal surface profile or changes of ciliary activity.

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A 0.2ml of histamine was injected into the bulla of the guinea pigs, and the mucociliary pathology was examined at 1, 3, or 8 days postinjection. 2.7×10^-6M of histamine produced temporary middle ear effusions (MEE), and that of 2.7×10^-4M did prolonged MEE. 2.7×10^-6M-histamine induced mucociliary dysfunction, but the function in the tube and the proximal mucosa recovered at 8 days. The functional recovery in any location was not fully demonstrated even at 8 days when 2.7×10^-4M-histamine was injected. In conclusion, histamine could be involved in otitis media with effusion through its effect on the mucociliary system.

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The clearance of ³H-Salmonella endotoxin inoculated into the middle ear and its fate were studied and the following results were obtained. 1. Neutophils (6-24h) and then macrophages (48-120h) migrated into the middle ear but these cells contained few endotoxin grains. 2. The radioactivity of the endotoxin decreased quickly in the middle ear untill 6 hours but reappeared partially 12-24 hours after inoculation. Most of them was cleared 48 hours after inoculation. 3. The histological changes of noncliated mucosa was observed whereas no significant change in ciliated mucosa. These results suggest that free endotoxin may cause severe damage of the middle ear mucosa when tubal function is impaired.

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Lipopolysaccharide (LPS) from K. pneumoniae reduced ciliary activity from the tubotympanum. The effect was correlated with the concentration of LPS, and the largest effect was observed on the distal middle mucosa. Tympanic inoculation of LPS (10μg/ml) produced middle ear effusions in guinea pigs at 1 or 3 days postinoculation when the ciliary activity in the tube and the middle ear was depressed. At 7 days, however, effusions were not observed when the ciliary activity remained to be depressed only in the distal mucosa. The study has suggested that LPS from K. pneumoniae could be a pathogenetic factor of otitis media with effusion, through its effect on the mucociliary system in the tubotympanum.

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The purpose of this study was to gain anatomical informations of eustachian tube and its accesory structures, such as the internal carotid canal, the tensor tympanic muscle and the middle cranial fossa in human temporal bones. For this study, using serial sections of normal temporal bones from 9 adults, each anatomical relations among those structures was observed at three different sections showing the orifice of the tympanum, the bony portion of the tube and the isthmus of the tube. In each case, individual variations were seen apparently in anatomical relations of the euctachian tube and its accesory structures.

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