The primary and secondary neurons of the auditory and vestibular nerve of the mouse were examined for the presence of substance P (SP) by an immunocytochemical technique. Mouse heads were decalcificated with EDTA at 4°C and SP was visualized with the peroxidase-antiperoxidase technique. The results were as follows.
1) No SP was detected in the spiral ganglion or vestibular nucleus.
2) A very small amount of SP was found in some cell bodies of the vestibular ganglion and a moderate amount was found in many cell bodies of the ventralmost part of the ventral cochlear nucleus.

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The external sulcus cells in the lateral wall of the cochlear duct extend cell cords into the connective tissue. To understand the three-dimensional organization of the cell cords, we removed the external sulcus cells with boric acid and osmic acid, exposed the connective tissue, and observed the holes for the insertion of the sulcus cell cords by scanning electron microscopy.
A zone perforated with the numerous holes appeared on the spiral ligament facing to the cochlear duct. The zone lay in the upper region of the area between the stria vascularis and the lateral edge of the basilar membrane and extended from the basal to the apical end of the cochlear duct. In the hook and first basal half turn, the holes mainly showed large, fusiform openings and deeply branched into the connective tissue. Toward the apex, the holes became smaller and shallow, showing round openings. The width of the perforated zone and the number of the holes per unit surface area of the spiral ligament decreased from the base to the apex and disappeared at the helicotrema. The regional differences in the organization of the external sulcus cell cords suggest that the external sulcus cells function closely relating to the regional auditory functions of the cochlear duct.

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Cross-links between stereocilia on guinea pig cochlea hair cell have been examined using transmission electron microscopy. The links have been seen in material fixed using (1) glutaradehyde/osmium and (2) glutaradehyde/ osmium/Ruthenium red. Side-to-side and row-to-row links form a regular lattice between stereocilia and consist of a number of strands. In the end of which are assoicated with electron dense material and at the mid-point between stereociliathe links often have a denser band visible along tha filament network. Guinea pig were exposed to the noise at an intensity of 110-120dB SPL for 2-3 hour. During the periods of noise induced threshold shift were examined. The stereocilia of the haircell were clumped together compared with control ears.

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By ³H-thymidine autoradiography in the cochlea of the normal adult mice, we have previously shown that (1) DNA synthesis occurs in the intermediate cells in the stria vascularis, mesothelial cells in the Reissner's membrane, epithelial cells in the basilar membrane, and cells in the spiral ligament (2) The basilar membrane has the shortest cell cycle (3) DNA synthesis does not occur in the supporting cells of the organ of Corti. In this study, we carried out the same autoradiography after injection of nitrogen mustard-N-oxide (NMO), which damages the outer hair cells. A few grains were detected in some supporting cells of organ of Corti and mitosis was seen in Claudius' cells. The labeling indexes of supporting cells, basilar epithels, and mesothelial cells of Reissner's membrane increased dose-dependently with injection of NMO, although that of stria vascularis was not affected by the dose.

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Recent studies have revealed that many samples of middle ear effusion obtained from the patients of otitis media with effusion (OME) contained endotoxin. The purpose of this study is to examine if endotoxin in the middle ear can cause sensorineural hearing loss (SNH). Lipid A (1-200 μg/ml), biologically active portion of endotoxin, was instilled into the tympanic cavity of the guinea pig. The morphology of the cochlea was examined at light or electron microscopic level. As early as three days after the instillation, both the organ of Corti and the stria vascularis showed considerable degeneration. The results suggest that lipid A or endotoxin may be one of the causes of SNH which is demonstrated in some of OME patients. Further study is necessary before conclusion can be drawn.

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The effects of Argon Laser irradiation to the inner ear of the monkey were studied morphologically. Argon Laser was introduced to the saccule and the utricle through the oval window after stapedectomy. The hair cell and supporting cell of the maculae were destroyed without rupturing the saccular wall and utricular wall, nerve fiber to the maculae and ganglion cells were decreased ten weeks after irradiation.

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Vestibules of two cases of delayed endolymphatic hydrops were examined ultrastructurally. The case 1 was a 27-year-old woman and the case 2 was a 16-year-old woman. The specimens were obtained by their translabyrinthic operations of the vestibular nerve section. In case 1, the macula utricle and the posterior crista, and in case 2, the macula utricle, the anterior crista, the posterior crista and the vestibular ganglion could be studied. These sensory organs showed the normal features. These findings indicated the histological evidence that the patients suffered a vertigo attack repeatedly because their peripheral vestibular sensory organs were intact.

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The ultrastructure of fine filamentous components was examined with TEM in the subepithelial connective tissue of the ampulla. These filaments varied in width from lOnm to 15 nm. In cross sections at high magnification, each filament had the shape of a polygon and consisted of some electron-dense spherules. These morphological findings suggested that they appeared to be identical to so-called microfibrils. The fibrils distributed sparser in deeper layer of the connective tissue. Sometimes, bundles of the filaments were oriented perpendicularly to the basement membrane. It seemed that they anchor the epithelium to the connective tissue.

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The fine structure of the vestibular ganglion cells in the macaque monkeys was studied with transmission electron microscope. Most cells were myelinated with compact myelin layers. The myelin sheath varied its thickness around one perikaryon. There was an alternating pattern of the perikaryal myelin between loose and compact lamellae. Over 400 serial sections showed that about 5% of the ganglion cells appeared unmyelinated without compact myelin layers. However, no remarkable ultrastructural differences were found between myelinated and umnyelinated perikarya.

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The present immunocytochemical study has demonstrated the presence of a dense fiber plexus containing calcitonin gene-related peptide (CGRP) in the vestibular end-organs in the rats. These fibers appear to originate from the central nervous system. And it was suggested that the possibility that CGRP acts as a vestibular efferent neurotransmitter.

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After injection of the HRP to the cervical, thoracic and lumbar spinal cord, the labelled neurons in the pontine and medullary reticular formation were observed.
The reticulospinal tract (RST) which originates in nucleus reticularis magnocellularis descended almost entirely ipsilaterally to the whole spinal cord. The RST which originates in nucleus reticularis gigantocellularis descended bilaterally to the whole spinal cord. The RST which originates in nucleus reticularis pontis caudalis descended bilaterally to the whole spinal cord.
The RST which originates in the nucleus reticularis gigantocellularis is important as a system which relays the information of the labyrinth to both ipsi-and contralateral sites of the whole spinal cord.

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Using 64 guinea pigs, efficacy of intratympanic administration of steroid with CMC (carboxylmethylcellulose) as an application for the inner ear was examined. Dye solution without CMC administerd in the middle ear was cleared from the middle ear through the eustachian tube after one day, while that with CMC was present 100% at 1 day, 67% at 4 days and 33% at 7 days. Uptake of steroid in perilymph by intratympanic administration with CMC was significantly higher than that by intravenous administration at 3 hours and 1 day, and that by intratympanic administration without CMC at 4 days and 7 days. These results indicate that intratympanic administration of CMC steroid is effective for prolongation of retension of steroid in the middle ear and uptake of steroid in the inner ear.

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The round window membrane (RWM) permeability to human serum albumin (HSA) was investigated in sensitized chinchillas with HSA. The effect of a corticosteroid agent (Triamcinolone) on the RWM permeability was also studied. HSA could not be detected in either the perilymph (PL) and CSF of normal chinchilla within 1 hr after instillation into the middle ear bulla. However, significant level of HSA could be quantified in the PL of which peak was observed at 24 hrs after instillation. In sensitized chinchillas, HSA level in the PL at 12 hrs after instillation was significantly higher than that of normal chinchilla (p<0.01). HSA levels in the PL significantly decreased by a steroid treatment.

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Pressure transmission properties from the external ear canal to the middle and inner ears were studied in guinea pigs. When pressure of 200 mmH₂O and -200 mmH₂O was applied to the ear canal, the middle ear pressure correspondingly raised to 149±36 mmH₂O and dropped to 96 ±32 mmH₂O, respectively, on the average for 6 ears; the inner ear pressure was 131 ±29 mmH₂O and 79 ±33 mmH₂O. When the ossicular chain was disrupted, the middle and inner ear pressures were the same level as those with the intact ossicular chain for the positive pressure load but decreased further for the negative one. When the round window was closed, the middle ear pressure unchanged for the positive pressure load but decreased further for the negative one; changes of the inner ear pressure were predominantly diminished.

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Effect of round window membrane rupture on cochlear blood flow was investigated using nonradioactive microspheres in guinea pigs. When the round window membrane was ruptured with a fine needle under ordinary inner ear pressures, cochlear blood flow did not change significantly. However, in the case when the inner ear pressures were high enough to interrupt the cochlear blood flow, the rupture of the round window membrane lowered the inner ear pressures and restoration of cochlear blood flow was observed. Thus, the round window membrane was a “safety valve”to restore cochlear blood flow under the condition of extremely high inner ear pressures.

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Three-dimensional reconstruction of the inner hair cells and their nerve endings of the guinea pig cochlea were performed from serial thin sections by means of computer graphics, and morphometric data was obtained. The methods for computer-aided reconstruction and morphometry were reported elsewhere.
The number of afferent nerve endings in the basal turn (average 25) was higher than that in the third turn (ave. 17). The majority of afferent endings (81%) were accompanied by the typical synaptic bodies in the hair cells, and several efferent endings were found to have synaptic contact with the inner hair cells.

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The computer-aided serial section reconstruction system (SERSERS) was employed to elucidate the entire configuration of the vestibular aqueduct in the human temporal bone. The advantage and the disadvantage of this method are discussed in comparison with several conventional methods such as X-ray visualization, plastic casting and graphic reconstruction. In spite of some limitations encounted such as difficulty in putting a mark on each section or time consumption in data imput, SERSERS may be useful in study of the vestibular aqueduct since a three-dimensional model can be observed from multidirectional point of view.

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Three-dimensional computer reconstruction of the osseous and membranous labyrinths was undertaken from histological sections of the temporal bone. Fifty-four sections were converted to two-tone color images of the osseous and membranous labyrinths, and by using seeing-through function of the computer system, simultaneous reconstruction of both labyrinths was possible. Thus, the membranous labyrinth could be seen through the osseous labyrinth. Enlarging the input images and smoothing permitted clearer representation of the reconstructed labyrinth. Three-dimensional reconstruction is useful in understanding the spatial relationship of various structures of the temporal bone. Advances in computer technology will solve technical problems, but such problems as reference points and conversion of histological sections to input images will remain.

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In making three-dimensional reconstruction of histologic sections, it is important to determine standard points. However, it is difficult to determine these points in celloidin-embedded specimen without making injury to it. We have developed a method of determining standard points without making injury to the specimen. In this method brain was embedded in celloidin with the specimen. After determining the angle of the celloidin block, holes were drilled vertically into the embedded brain. The specimen was then processed according to the conventional method. Three-dimensional reconstruction was made from the sections thus prepared.

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Information about the eardrum impedance is of some significance for the diagnosis of middle ear disorders, and for simulating the acoustically relevant properties of an average human ear. But no convenient commercial system is available for the precise measurement of the human eardrum impedance. Recently the ear canal transfer function was measured by use of short sound pulses, and the precise eardrum impedance was derived from it. This technique for the impedance measurement is based on acculately estimating the sound pressure of three points in an ear canal, minimizing standing waves. In this paper the author describes a system to measure the human eardrum reflectance by estimating the standing wave patterns'in the occluded ear canal.

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During the careful follow-up study of otitis media in children, the tympanic membrane changes are usually reversible. But some may progress and become irreversible.
The destruction or absence of the middle collagenous layer of the tympanic membrane occurs in the atelectatic ear has already been shown histologically.
What actually happen in the tympanic membrane during the development of otitis media? We must learn more about the biomechanical patho-physiology of the tympanic membrane.
In this study, we attempted to examine experimentally the vacuum effect on the tympanic membrane in relationship to the size of the middle ear air system.
Collagen membrane used as a model of the tympanic membrane was examined with the tensile fatigue testing machine.
1. We were able to show the endurance limit of this membrane to the pressure.
2. Collagen membrane was more deformed in the narrow air system.
Biomechanically, intratympanic repeated negative pressure should be a major factor in the etiology of the atelectatic ear drum.

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A tension testing machine capable of measuring microload was manufactured and used to study the mechanical properties of the tympanic membranes in guinea pigs. The three part of tympanic membrane-anterior, inferior and posterior-were studied in both fresh tympanic membrane and formalin-fixed tympanic membrane. The relative elongation, elastic modulus and tensile strength of fresh tympanic membrane was 126.0%, 1.87kgf/mm², and 0.33kgf/mm², respectively. In formalin-fixed tympanic membrane, the relative elongation was 44.7%, elastic modulus 0.92kgf/mm², and tensile strength 0.11kgf/mm². The results indicated that no significant difference existed among these three parts in relative elongation, elastic modulus and tensile strength both fresh and formalin-fixed cases.

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Temporal bones are extracted from fresh cadavers, and the condition of only the ear-drum attachment to the temporal bone is made. Then, the dynamical characteristics of the ear-drum of the specimen are measured with a newly developed measuring apparatus. At the same time, applying the impedance theory of the tube to the external auditory canal and the energy method to the ear-drum, the equation corresponding to the output of the apparatus is obtained. Comparing the measurement results and the numerical results, the Young's modulus E_E and Damping parameterξ_E=c_E/2 (m_Ek_E) ^1/2 are determined to be E_E=3.25×10⁸ dyn/cm² andξE=0.158.

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The thickness of the tympanic membrane was measured under a microscope, using human serial horizontal sections of 96 normal temporal bones from 78 subjects. Ten different sites of the tympanic membrane were chosen for measurement, and the average of thickness was compared for each site. Tympanic membranes were grouped according to the subject's age into ten-year intervals, and their thickness was measured. The thickest site was the mid point between the short process and the posterior edge, because the lamina propria was remarkably thicker. There was almost no difference in the thickness of the tympanic membrane among the various age groups.

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The epithelial cells of human tympanic membrane are observed using scanning electron microscopy. The epithelial cells are collected by a double-sticked sero-tape attached on tip of a teeth stick from human tympanic membrane, which seems a normal appearance. The epithelial cells have a various surface structure under scanning electron microscopy. They can, generally, classify according to their surface structure following a five types: 1. Surface with papillomateus projections, which are cylindrical or tongue-like shape. 2. Surface with plica or falte like structure. 3. Surface with a slightly convex protrusion. 4. Surface with small hemispherical projections and 5. almost smooth surface. Those findings are briefly discussed.

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Developmental anatomy of the tympanic membrane and its relation with the malleus handle was studied using fetal temporal bone specimens. During 16th week of gestation the intermediate mesodermal layer which consist of two laminas-radial layer laterally and circular layer medialy-originate around the tympanic ring as loose connective tissue. The inner circular layer hold the malleus handle and fuses with the periosteum (or perichondrium). The outer radial layer which is thicker than the outer circular layer contains copious blood vessels. After 30th week of gestation conjunction between malleus handle and inner circular layer become loose and lost except outer surface of the malleus handle. Only at the tip of the malleus periosteum is thick and hold by the circular layer which seems to become the umbo.

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Many otologists were interested in the cholesterol level in the cholesteatoma matrixs and discussed the origin of this cholesterol. At present, the origin of the cholesterol is uncertain. In this study, we cultured the skin of the external auditory canal and ear drum, in-vitro and measured the synthesis of cholesterol in these cultures by using radioactive material. The results showed that cholesterol, especially esterified cholesterol is actively synthesized in these skins. This study appears to indicate that the cholesterol of the cholesteatoma matrix is actively produced in the cholesteatoma matrix.

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The tympanic membrane of frog is exposed directoly to the external environment. It is almost round in shape, and is thickened in the central part. Circumferential part is thinner than central part. The tympanic mebrane was uniformly spread along the outer edge of the annular cartilage, and no pars flaccida was observed. Fibrous tissue of the lamina propria consist of radial collagen fiber. The tip of the columella consists of cartilage, loosely adhered to the dorsal surfase of the center of tympanic membrane. Along the columella, there was a loose, wrinkly connective tissue between the tympanic membrane and columella, that is the archetype of malleus handle. The annular cartillage was considered to be the original form of the external auditory canal.

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Bull frog tympanic membranes were observed macro-and microscopically. They were large, rounded and superficially located at the temporal region of the head. The columella was also large and its lower tip was tightly attached to only the center of the membrane, however, the greater part of the columella was loosely connected to the inner surface of the tympanic membrane with a soft tissue fold. The peripheral zone of the tympanic membrane was thin (approximately 0.07mm) and the central zone of it was thick (maximum 0.84mm). The tympanic membrane was consisted of five layers; epithelial layer, subepithelial connective tissue layer, fibrous layer, submucosal connective tissue layer, mucosal layer. The pseudo-stratified ciliated epithelium with goblet cells existed on the surface of the columella.

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A histological study was made of the normal development of the tympanic membrane of ddN mice from the twelfth day of gestation to 14 days after birth. The genesis and later development of the tympanic membrane is intimately related to the formation of the external auditory meatus. After reaching near the tubotympanic recess, the primitive external auditory meatus extends along the recess until terminating on the eighteenth day of gestation. From 1 to 7 days after birth, the organs peculiar to the internal and external sides of the primordium of the tympanic membrane develop, and on 8 days after birth, a separation occurs between the two sides. The side facing the external acoustic meatus moves toward the osseous or cartilaginous portion of the meatus as it expands, leaving the tympanic membrane which develops after birth.

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To investigate the healing process of traumatic perforation in tympanic membrane, we cultured the tympanic membrane. The tympanic membranes of guinea pigs were cultured by a collagen gel cultures method. The ultrastructure of the cultured tympanic membranes were observed at various intervals through the transmission electron microscope. At the 18th Japan Society of Ear Research Conference, we reported that the tympanic membrane could be cultured for three days. This time, we tried different culturing methods and found that the tympanic membrane could be cultured for 7 days. To develop better culturing methods of the tympanic membrane, we will continue our research.

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The comparison of sound conductivity and mode of vibration of the autogeneous and homograft tympanic membrane, and temporalis muscle fascia in cats were studied. Pure tone sounds in 4 frequencies were emitted against the materials and sounds behind them were measured, and at the same time, interference fringes were observed by means of time averaged holography. The loss of SPL behind 3 materials was the least in 500Hz ranging between 1-2dB, while the largest in 4KHz ranging between 6-9dB. Comparison of interference fringe using holography among 3 materials showed rather clear pattern in the autogeneous and allograft tympanic membrane, while less clear in fascia. With the combination of these two methods, further physical information on the tympanic membrane will be acquired.

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This reports the results of a mainly SEM study of corrosion casting method in the tympanic membrane (TM) and round window membrane (RW).
1) normal TM and RW; In the pars tensa, blood vessels run straight forwards along the handle of the malleus. Otherwise in the pars flaccida, these vessels didn't run straight but were like a mesh of a net. Meanwhile distribution of RW vessels were similar to that of the pars flaccida.
2) TM and RW perforation; Repair of TM perforation needs 2 vascular areas. 2 vascular areas are annular ring side and malleus side of the TM perforation. But in case of only one vascular area around the TM perforation, we suggest that the perforation is not closed or it's closed period prolongs. And we could see that on the recovery of RW perforation, vessels of middle ear mucosa approached to the perforation.

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The vascular supply of the rabbit tympanic membrane was studied by means of stereoscopic microscopy after vital staining with Indian ink and light microscopy of serially sectioned specimens. The results were as follows: 1. Three dominant vascular plexuses could be distinguished in the tympanic membrane, that is, the pars flaccida, the manubrial part of the pars tensa and the part of the fibro-cartilaginous ring. 2. Denser vascular supply was found in the subepidermal layer than in the submucosal layer throughout the whole tympanic membrane. 3. In the inflamed tympanic membrane, the invisible vessels dilated and many minute branches appeared in the pars tensa.

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Tympanic membrane of guinea pig was iontophoretically anesthetized, and studied histologically. Edema was recognized in subepidermal connective tissue layer, and basement membrane was detached from the basal cells 2 hours after iontophoresis. Epidermal layer between the handle of the malleus and the bony annulus peeled and retracted towards the bony annulus 8 and 12 hours later. Two days after iontophoresis, the epidermal cells began to migrate toward the handle of the malleus. Four days later, the epidermal layer was hyperplastic and remarkably thickened.

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We observed the effects of liquid anesthetic on the tympanic membrane of guinea pig. In case liquid anesthetic was applied to the tympanic membrane for five minutes, the epithelial layer was swollen and in case applied for fifteen minutes, a part of the epithelial layer was dropped out. After two weeks from the application for five minutes, the pathohistological effects of epithelial layer still remained, but the naked eye inspection did not show any problem. After one week from the application for fifteen minutes, the inflammatory symptom was demonstrated and after two weeks the perforation showed all the part of the inflammatory symptom.

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In this study, we suggest that the pathological changes in the tympanic membrane in OME should be classified into four stages. A small sample of TM tissue was obtained from a part of the anterior inferior quardrant of TM. Light microscopic and electron microscopic findings: (1) The outer and inner fiber layer of TM gradually thinned and disappeared. (2) The submucosal connective tissue was considerably thickened and composed of hyperplastic connective tissue with edema finally changing to fibrous tissue. From these results, we suggests the following four stages.
Stage I: Outer and inner fiber layers are observed.
Stage II: The outer fiber layer is observed but the inner fiber layer has disappeared.
Stage III: Most of the outer fiber layer has disappeared.
Stage IV: Both layers have disappeared and been replaced by connective tissue.

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The human tympanic membrane (pars tensa) and middle ear mucosa were investigated in patients with secretory otitis media to clarify its retraction process. Biopsy specimens were obtained at tympanostomy tube insertion and observed utilizing a TEM. The pathological changes of the tympanic membrane were found mainly in the lamina propria, characterized by the proliferation of the connective tissue and capillary, irregularly arranged collagen fibrils, disappearance of fiber bundles. Occasionally the epidermis of the tympanic membrane became thicker than usual. However, morphological changes in the middle ear mucosa do not show any definite correlation with those of the pars tensa.

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Loss of collagen fibers at the site of adhesion and disorientation of collagen bundle at the nonadhered site are the common observation of adhesive otitis media. Distraction of capillary blood vessel and the presence of ciliated epithelium at the nonadhered site may indicate the long standing mild infection as the pathogenesis of adhesion.

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It has been suggested that mast cells in the pars flaccida of rat, and their chemical mediators (especially histamine) are involved in the pathogenesis of otitis media with effusion (OME). In the present study, mast cells in the pars flaccida and middle ear mucosa of normal guinea pigs, and guinea pigs with experimental OME were investigated. A large number of mast cells were found in the pars flaccida and in the tympanal orifice of the eustachian tube of the guinea pigs. Experimental OME caused inflammatory changes in the structure of the middle ear mucosa and the pars flaccida. The effusion material from the guinea pigs with experimental OME was found to contain high levels of histamine. These findings suggest that mast cells of guinea pigs play an important role in the nathoaenesis of OME.

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The temporal bones in sixteen cases of leukemia patients were studied histopathologically, and especially the findings of leukemic changes of the tympanic membrane were reported. The leukemic cell infiltration into the tympanic membrane was observed in eight cases (50%) and the hemorrhage into the tympanic membrane in five cases (31%). The leukemic cells infiltrated mostly into the subepidermal connective tissue layer of the tympanic membrane.
It was thought that the ear symptoms such as hearing impairment or tinnitus were caused by not only leukemic infiltration into the inner ear but also by infiltration into the tympanic membrane.

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Light microscopic and scanning electron microscopic investigations revealed remarkable morphological changes of the fiber arrangement in the middle lamina propria of the pathological human tympanic membranes. These changes were present mainly in the middle zone of the pars tensa. There were several fibers running in entirely different directions among the regularly arranged radial and circular fibers. These abnormal fibers had a tendency of forming fiber bundles of varying sizes and lengths. It is stressed that the normal fiber arrangement was undoubtedly disordered in the healing process of the inflamed middle lamina propria of the human tympanic membrane.

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Clinical characteristics of 3 major pathological entities of the eardrum, namely chronic myringitis, so-called eczema and acute purulent myringitis, were reported. The number of patients analysed were 82, 8 and 1 respectively. The lesions were either single (chronic myringitis) or multiple (eczema and acute myringitis) erosions or thin granulation. Though perforation of the eardrum was often found in chronic myringitis, middle ear involvement seldom occurred in any of the 3 pathologies. Recurrence is common in chronic myringitis and eczema. Bacteria are the causative factor of acute myringitis, but no exact causes have been found for the other 2 diseases thus far.

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Construction of calcified substances in tympanic membrane in one case of tympanosclerosis and two cases of chronic otitis media collected in tympanoplasty, were analyzed at the molecular level using laser-Raman spectroscopy and relationship between the formation process in the calcified substances and history of ear illness was discussed. Results are summarized as follows: Calcified substances having two different constructions (tympanosclerosis type and chronic otitis media type) were detected. Three strong intensity bands at about 960 cm^-1 due to ν₁ (PO₄^3-) on the former spectra and at about 1070 cm^-1 and 730 cm^-1 due to ν₁ (CO₃^2-) and P-O-P (sym. stretch.) on the latter spectra were observed respectively. Intensity ratios of amide I/ν₁ (PO₄^3-) on calcified substances were about 0.8 in chronic otitis media type and about 0.5 in tympanosclerosis type. From the result of conformational analysis on a cross section of epithelial layer, it may be suggested that tympanic membrane in chronic otitis media is consisted of at least two types of protein.

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Histopathologic findings of the human tympanic membrane following middle ear infection have been presented and described deviding into acute and chronic groups.
1. Acute myringitis: Two cases of acute myringitis which occurred in association with acute suppurative otitis media have been reported. It is characterized by large serous blebs between the fibrous and dermal layers (Fig. 1 and 2).
2. Chronic inflammatory changes of the tympanic membrane:
1) Thickening or atrophic changes of the tympanic membrane: In chronic otitis media, a fibrosclerotic thickening of the fibrous layer or a thin layer of epidermis and mucous membrane (replacement membrane) is frequently observed (Fig. 3 and 5). Thick and thin areas may occur in the same tympanic membrane and may be associated with plaques of hyalinized collagen (tympanosclerosis).
2) Retraction pocket: A retraction pocket consists of an invagination into the middle ear space of a replacement membrane and may occur either in the pars tensa or pars flaccida. A typical attic retraction pocket is shown in Fig. 4.
3) Perforation (Fig. 6).

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The purpose of this study is to offer basis for clinical application of the antidromically evoked facial nerve response to intratemporal facial nerve paralysis. Waveforms recorded from the recording electrode placed on the geniculate ganglion and the horizontal segment were analyzed in regard to sites of lesions. Lesions were modeled by sectioning the facial nerve or applying 4% Lidocaine solution on the facial nerve at various sites. The normally evoked triphasic wave turned to biphasic, when the presumed lesion was shortly central to the recording site. Monophasic waves were recorded when the lesion was at the recording site or peripheral to the recording site. The results of this study give basis for clinical interpretation of antidromically evoked responses in cases of intratemporal facial paralysis.

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Funicular structure of the facial nerve was investigated with adult guinea pigs by cross and vertical serial sections stained with toluidin blue. The facial nerve is composed of a single funiculus at the origin of the chorda tympani. It is divided into a few large distorted funiculi by a thin perineural sheath at just proximal part of the stylomastoid foramen. Most of the large distorted funiculi further repeat divisions and the perineural sheath becomes thick and round, although some funiculi fuse together at the distal part of the stylomastoid foramen. At the 2 mm from the stylomastoid foramen, many small round funiculi are seen in the outer part of the facial nerve, since the divisions of funiculus are more remarkable in the outer part than the central part.

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The rabbits received injections of various volumes of Indian ink into the facial nerves from the stylomastoid foramen, then, the cranial bones with brains were fixed by intravascular perfusion with 10% folmaldehyde. Observation of the serial sections of their cranial bones with brains revealed Indian ink infiltration into the subarachnoid space along the facial nerve, the auricular branch of the vagus nerve, and the tympanic nerve. Furthermore, from the tympanic ganglion to the tensor tympani muscle along the tensor tympani nerve and to the tensor plati muscle along the tensor palati nerve.

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Morphological differences between secretory cells of human ceruminous glands of the wet and dry types were examined. The height of secretory cells was various, tall, medium or low, in both wet and dry type glands. Differences were observed in the morphologic feature of the tall cells and the cells of medium height between the two type glands. The Golgi apparatus was well developed in the wet type gland. Light granules were frequent in the wet type gland. Apical protrutions were generally large and round and bore “microvilli and the light granules” or “very few microvilli and no light granules” in the tall cells of the wet type gland.

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Lever ratio of the ossicles and input impedance of the cochlea with the stapes were measured in nine human cadaver temporal bones using video measuring system. The cochlear impedance measurement was done immediately after the ossicular lever ratio measurement. The average lever ratio was about 10 dB at low frequencies and increased gradually above 1.4 KHz. The average cochlear impedance was 0.7 ± 0.3 MΩ at 1 KHz. There was no significant correlation between the lever ratio and cochlear impedance. Our results suggested that larger lever ratio doesn't always mean higher sound pressure transmission through the middle ear.

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