For severe otitis media with effusion, insertion of a ventilation tube is performed for the purpose of ventilation of the middle ear cavity and normalization of eustachian tube function and the middle ear mucosa. The ventilation tube is left in place for as long as several months or even a few years. However, the effect of insertion of a ventilation tube on vibration of the tympanic membrane is unknown. Therefore, we observed the effect by means of time-averaged holography using human tympanic membranes. The following results were obtained. After insertion of a ventilation tube, the tympanic membrane vibratory pattern was not obviously changed, but the vibratory amplitude of the tympanic membrane was decreased, especially at 500Hz. Generally speaking, the change caused by insertion of a ventilation tube was very small.
The effects of epidermal growth factor (EGF) and transforming growth factor-β (TGF-β) on the healing process of tympanic membrane perforations were studied in guinea pigs. The diameters of the perforations were measured daily using an operating microscope. The perforations healed rapidly, when hypertrophy of the epithelial layer was accelerated by EGF. Closure of the perforations was inhibited, when regeneration of the middle layer was disturbed by TGF-β. Regression analysis on the diameters of the perforations revealed that spontaneous healing of the perforations was accelerated during the second half of healing process with simultaneous hypertrophy of the middle layer.
Repair of experimental Perforation of the tympanic membrane in the guinea pig was observed by light and polarized microscopy (surface preparation). The linear incision was done at right angles to the radial fiber bundles in the tympanic membrane of 34 guinea pigs. The perforation of the tympanic membrane closed one week after the incision. The capillary appeared after two weeks and the fibrils could be found after four weeks. The mechanical strength of the tympanic membrane recovered up to 70% of the strength of the normal tympanic membrane after seven weeks. The radial fiber bundles were not yet repaired after ten weeks.
Observation of fine vibration of both the human and the guinea pig tympanic membrane being responded to various sound stimuli by using Ultrasonic Pulse Doppler Method has already been reported. This study is to present the measurement of the resonance frequency and Damping Ratio of both the human and the guinea pig ear drum in vivo using the same Ultrasonic Pulse Doppler apparatus previously reported, with a fine probe of 1mm in diameter. We'd like to emphasize the possibility of the measurement of mechanical properties of the human tympanic membrane and on its application to the audiological investigation.
Thirty guinea pigs were used in this experiment. A piece of skin taken from superior and inferior part of the external auditory meatus and from the auricle were implated subcutaneously in the back. They were removed between the 1st and the 18th week postimplantation for the histological study. Epidermal cyst was formed in all the animals beyond two weeks. Regardless of origin of the skin, the histological findings appeared to be same. No further growth of cyst was recognized after the 2nd week. In some animals, the cysts were cut in half in order to expose the contents directly to the surrounding tissue between the 2nd and the 3rd week. Even after this procedure, the size as well as the histological findings were same regardless of origin of the skin. The results suggest that the skin of superior part of the external auditory meatus has no specific growth potentiality to form epidermal cyst.
Obliteration of temporal dorsal bullae using hydroxyapatite granules (HG) was performed to investigate the biocompatibility of HG in the mastoid cavity. The specimens, prepared by undecalcification hard tissue technique, were observed one year after HG implantation. The temporal dorsal bullae were observed to be obliterated completely by HG and bone. The bone and HG were interdigitating tightly without connective tissue. Physiological new bone formation, possessing features such as osteon-like structures and Haversian canals, could be recognized. It is concluded that HG is a useful material for mastoid obliteration with tympanoplasty.
The demineralization process of a thin small synthetic apaceram disc embedded into the subcutaneous tissue in the dorsal of a rat for 3 months and the process of remineralization on the surface of this tissue were observed using laser-Raman spectrometry and fluorescence microscopy. From the results obtained, it is suggested that both demineralization and remineralization occur in vivo after contact with the apaceram disc.
Neutrophil elastase (NE) levels in ear discharges from 15 chronic suppurative otitis media (CSOM) patients were measured by sensitive sandwich ELISA in order to discuss roles of NE in the prolonged middle ear inflammation of CSOM. Levels of NE complexed with α1-antitrypsin were 13.7μg/ml in CSOM and 7.8μg/ml in middle ear effusions (MEE) from chronic otitis media with effusion (OME). However, total NE levels in CSOM (162μg/ml) was significantly higher than that in chronic OME (16.5μg/ml). These results indicate that majority of NE in ear discharges from CSOM patients is occupied by free NE. Total NE levels in CSOM were not parallel to the results of cytological study, suggesting that free NE could contribute to the inflammatory reaction taken place in the middle ear mucosa even after cell lysis of neutrophils.
Compliant tube, which is forced to open and close easily by low pressure, is a new concept of the eustachian tube abnormality. This abnormal condition is supposed to be one of the causes of various middle ear diseases like otitis media with effusion and cholesteatoma. In this report we performed four different eustachian tube function tests (inflation-deflation test, forced response test, eustachian tube function in pressure chamber test and negative pressure test) before and after cutting the third branch of trigeminal nerve, using rats. Finally we succeeded to make the experimental compliant tube.
Ultrastructural Localization of sialic acids on the guinea pig eustachian tube and middle ear mucosa was studied using lectin-gold technique of Limax Flavus Aggutinine. Under normal conditions, sialic acids were detected in the secretory granules of the goblet cells, on the plasma membrane of the cilia and microvilli of the ciliated cells. The periciliary space was margined with membranous structure and sialic acids were distributed on its inner surface. On the other hand, in the case of experimental otitis media with effusion, the mucous layer covered the surface of the cilias in which a large amount of sialic acids was detected.
Lectin binding on the guinea pig middle ear epithelium was ultrastructurally analyzed using eight biotinylated lectins in conjunction with streptavidin-gold complexes or using colloidal gold labelled lectins. The lectins were Canavalia ensiformis, Triticum vulgare, Griffonia simplicifolia II, Datura stramonium, Maclura Pomifera, Arachis hypogaea, Ricinus communis I, and Limax flavus. It is suggested that different sugar residues are present on the glycocalyx of different cell types of the epithelia in the middle ear.
Opening pressures of the eustachian tube were measured before and after tubal washing by several solutions (surfactant, phospholipids, detergent, and saline solution). The pressure reduction ratio were caliculated, and both reduction ratios of surfactant and detergent were significantly larger than that of saline solution. There were no significant differences between the pressure reduction ratios of phospholipids and that of saline solution.
The membrane potential is negative charged and it works on the filtration of substances as a charge barrier. PEI (polyethyleneimine, M. W. 1800) is a strong cationic tracer to identify the anionic sites histologically. In the present study, PEI was used in the middle ear and the eustachian tube of the guinea pigs, and histamine or PAF (platelet activating factor) were administrated in the different cases. The results showed that the particles of PEI were arranged regularly along the capillary basement membrane in the middle ear and the eustachian tube. But in the cases of addition inflammatory mediators the number of PEI particles was decreased, which may possibly be induced the condition of hyperpermeability of membrane.
Primary Culture of chinchilla middle ear was successful. An assessment of the normal morphology and ultrastructural changes of the primary explants and outgrowth cells was completed. The differentiated cells like ciliated, non-ciliated (secretory) cells were found in this culture system. But those cells tended to disappear as the day went in culture. This model may prove useful for studying the various abnormal conditions of the middle ear.
Explants from middle ear and tracheal mucosa of the guinea pig were cultured using collage gel method, and their proliferative characteristics were studied. The outgrowthal area of cultured cells was examined quantitatively and compared at each location for periods of up to ten days. The specimens sampled from the sites with cuboidal half-ciliated epithelia, which formed as large as tenfold out-growthal sheets from the initial explant, showed higher proliferative ability than the sites with pseudostratified ciliated epithelia.
Culture of explants of middle-ear epithelium in serum-free medium was successful. Cultured middle-ear epithelium was observed by phase-contrast microscopy (PCM), light microscopy (LM), and scanning electron microscopy (SEM). In these outgrowths, the majority of cultured cells were flat polygonal, but ciliated epithelium was also seen. The best proliferation was found on 16 days after K-GM medium was changed. This culture system should be a study of the differentiation of middle-ear epithelium in vitro.
13.0day rat embryos were cultured for 36 hours in the whole embryo culture system. Continuous flow of mixed gas consisting of 5%CO2 and 95%O2 were maintained in the culture bottles through the duration of culture in this series. The cultured embryos were histologically examined and compared with 13.0day embryos especially on the ear region. In 13.0day embryo, branchial archs remained and any anlage of middle ear structure was not developed yet. On the other hand, in cultured embryos, pinna and external auditory canal were developing and previous otocyst had developed to vestibular, cochlear and semicircular canal portions in shape. The tubotympanic recess extended in to the middle ear region and the stapedial anlage appeared adjacent to the developing otic capsule.
To determine the effect of killed nontypeable H. influenzae on the ciliary activity of the middle ear mucosa, two experimental groups and control group are designed (Group A, saline inoculation into the middle ear; Group B, killed H. influenzae inoculation; Group C, three subcutaneous injection of H. influenzae with Freund's complete adjuvant before inoculation of it into the middle ear). The ciliary movements are analyzed by photo-electric method. Ciliary movements are suppressed by inoculation of killed H. influenzae inoculation in both group B and group C. Suppression of the ciliary movement in group C persists longer than group B. Therefore, immuno-logical mechanism may enhance the suppression of ciliary movement induced by endotoxin of H. influenzae.
Effect of middle ear effusions (MEEs) from patients with OME on the mucociliary system were studied, by the use of in vitro and in vivo experimental models. In the presence of the medium containing serous MEEs, the ciliary activity from the eustachian tube demonstrated significant decrease as early as 36 hours post-culture. On the other hand, significant ciliary depression was observed as early as 6 hours in the presence of mucoid MEEs. Intratympanic inoculation of human MEEs induced serous OME in the guinea pig at 3 and 7 days. Such incidence was higher in animals injected with mucoid MEEs than those with serous ones. More obvious mucociliary dysfunction was also observed in animals injected with mucoid MEEs. Our study could indicate that effusions present in the ear contributes to the persistence of this disease.
This study was undertaken to establish whether or not DSPC (disaturated phosphatidylcholine) was present in the middle ear effusion (MEE). Our results showed that DSPC/PC ratio of MEE was much higher than that of serum. These results suggested that the source of supply of phospholipid in the MEE might be not only blood but also middle ear mucosa.
Otitis media was effected in the right ears of 8 pigs and the left ears remained normal. Two of pigs were sacrificed at 2 days, I week, 2 weeks and I month after injection of glycerin. The samples for electron microscopy were obtained from the Eustachian tube, the middle ear cleft and the air cell system. In the inflamed Eustachian tube and middle ear cleft, the epithelial cells were detached, the intracellular junction ruptured in several places and the cilia missing or deformed. But these features coexisted with features indicating increase the number of the secretory cell. The injured epithelial cells in the Eustachian tube regenerated in a shorter time than those in the middle ear cleft.
Squamous metaplasia of the middle ear mucosa was observed in inflamed ears induced in pigs in a series of experiments. The character of the stratified squamous epithelium caused by the metaplasia was then analyzed. The degree of inflammation was much greater in the ears with the squamous metaplasia. In contrast with the stratified squamous epithelium observed in the human aural cholesteatoma, in these cases of squamous metaplasia continuity to the ear drum was not seen, and there was very little keratinization of the epithelium and bone destruction. From these findings, it was considered that the formation and character of the metaplastic squamous epithelium in these cases is quite different from that in the human aural cholesteatoma.
Cholesterol granuloma consisted of various kinds of granulation tissue cells. Short or large cholesterol needles, which appeared as empty spaces in the sections were scattered in the granulation tissue, frequently in a pool of red blood corpuscles. They were also noted in and/or adjacent the giant cells. In the cytoplasma of giant cells the cholesterol needles were surrounded by mitochondria and lysosomes, and they were partly covered with some darkly stained lipid-like amorphous material. An indented nucleus spiked by a cholesterol needle was sometimes detected in the multinucleated giant cell. Since the giant cells in cholesterol granuloma possess similar ultrastructural properties to actively phagocytic histiocytes, they may play an active role in the absorption of cholesterol crystals.
The purpose of this investigation was to evaluate the pathological significance of bacterial flora on adenoid in otitis media with effusion. On the bacterial investigation on adenoids, S. mitis and S. sanguis were found to be major bacterial species. Therefore, We measured the antigen titers of alpha streptococci and the specific antibody titers to the antigens in middle ear effusion by ELISA. The alpha streptococcal antigens were detected in 24.4% of samples with the range of 1×104 to 1×108 CFU/ml. The IgG to S. mitis was detected in all samples, and the mean antibody titer was 59.94±7.43 times to that of volunteer's serum.
The bacterial adhesion to the mucosal surface is an initial event in the infection process. We investigated adhesin receptors of Streptococcus pneumoniae type 19 in the middle ear mucosa by the method reported by Nowicki et al. S pneumoniae were found to attach to epithelial cells of the middle ear mucosa and to accinal cells of the gland in the eusthacian tube. The pneumococcal attachment to the middle ear mucosa was inhibited by N-acetyl-D-glucosamine. The presence of pneumococcal adhesin receptors in the mucosal tissues, not only on the epithelial surfaces, suggests the bacterial stay in the tissue and it may cause the prolongation of the infection.
Progressive change of the round window membrane (RWM) after daily injection of endtoxin (Sigma, 10μg/ml, 50μg/ml) in the middle ear cavity were obsered by electron microscopy and the permeability change of the RWM was examined using horse radish peroxidase (HRP) as a tracer. Three days after first injection of endtoxin, mild edema ocurred in the subepithelial space of the RWM, and small number of granulocyte and a few mononuclear cells appeared. After seven days, edematous changae of the RWM was more pronounced than that in the three days group, and further, destruction of the inner layer was found sporadically.
To clarify the biochemical difference between pediatric and adult middle ear effusions (MEEs), we analyzed the protein components from MEEs of 3 children and 3 adults by electrophoresis. High molecular protein components (280 and 265 kDa proteins), which contained in sera in the concentrations less than 2.5%, were not detected in MEEs even in trace amounts. Mucin was comprised about 30% of the total protein in mucous MEEs and the weight ratio of mucin to albumin in mucous MEEs was 2.69, but serous MEEs from adult patients did not contain mucin.
The purpose of this study was to get a baseline information of the molecular constituents including extracellular matrix (ECM) in the chinchilla middle ear mucosa using immunohistochemistry. The results demonstrated that collagen types I and III were found in the submucosal layer, type IV collagen and laminin in the basement membranes, fibronectin in the submucosal layer and in the epithelial cell surface, and keratin in the epithelial cells. Few keratin-positive epithelial cells could be seen in the bulla, whereas almost all epithelial cells were positive with keratin in the eustachian tube mucosa and in the nasal mucosa. The number of keratin-positive cells in the bulla mucosa remarkably increased after Streptococcus pneumoniae inoculation in the middle ear cavity and these keratin-positive cells still remained in the convalescent period. These results indicate that synthesis of keratin may be the result of cell injury and, probably, keratin have an active regulatory role in the process of epithelial cell differentiation in the middle ear.
Thirty two guinea pigs were inoculated with either Sendai virus or measles virus into their middle ear and subsequently the round window membrane (RWM) and the inner ear were investigated by electron microscopy and immunofluorescent microscopy. RWM initially demonstrated pathologic change of the epithelial layer. In more advanced lesion, whole layers of RWM were affected with occasional fibrosis adjacent to the mesothelial layer. However, the inner ear was usually spared. Daily administrations of steroid (hydorcortisone 10mg/kg) after measles virus inoculation caused more pronounced changes of the round window membrane and in 2 ears out of 6, destruction of the outer hair cells was observed in the lower basal turn.
The role of the virus in the pathogenesis of otitis media with effusion (OME) was studied. Intratympanic inoculation of 0.2mL of influenza A virus (104PFU/mL) or lipopolysaccharide (LPS) from K. pneumoniae (100ng/mL) was not able to induce mucociliary dysfunction of the tubotympanum in the guinea pig. Intratympanic injection of such small amount of the LPS could induce middle ear effusions at 1-7 days in each animal previously treated with such small amount of the virus. Functional and morphological examinations demonstrated depression of ciliary activity and deteriorated mucociliary clearance of the tubotympanum. Our conclusion is that virus is a factor predisposing to OME and even small amount of endotoxin could induce the disease in the presence of preceding viral invasion in the middle ear.
Otitis media with effusion (OME) was induced in chinchillas by various procedures and pathologic findings of these animals were observed to elucidate the pathogenesis of this disorder. Obstruction of the pharyngeal orifice, and inoculation of endotoxin or middle ear effusion into the tympanic cavity were the procedures of the induction of OME. Cytologic and biochemical findings (histamine and PGE2concentrations) of the effusion, and histopathology of the middle ear mucosa of these OME-induced chinchillas were compared with those of immune-mediated OME. Although there was a variety of degree of these changes, no significant difference was seen among OMEs induced by different procedures. OME is perhaps a multifactorial disease. Findings of this study suggest the difficulty in knowing the cause by the pathologic feature of tympanic cavity.
An injection of 104 viable type 19 Streptococcus pneumonia into the middle ear of guinea pigs results in the onset of acute otitis media. However, a 3-day intramuscular injection of antibiotics (40mg ABPC, 2mg DKB) completely inhibits the onset of otitis media, and no fluid is observed in the middle ear, even after the injection of 106 viable cells. On the other hand, when an injection of 104-106 viable cells and the same antibiotics were given to 6 guinea pigs that had been systemically sensitized to formalin-treated Streptococcus pneumoniae, sterile serous fluid was observed in the middle ear of all cases. Judging from the results of immunohistological examination using immunofluorescence, the mechanism for this result was thought to be type III allergy.
Antigen-antibody reaction or immune complex formation is one of the causative factors for otitis media with effusion (OME). We have reported suppression of immune mediated-OME by the transfer of mucosa derived regulatory lymphocytes in mice. In order to clarify the regulatory lymphocytes, mucosa derived regulatory lymphocytes were fractionated by treatment with monoclonal anti-Lyt1 or anti-Lyt2 antibodies. Mucosa derived lymphocytes were obtained from the spleen after oral administration of mice with ovalbumin. Transfer of remaining lymphocytes after treatment with anti-Lyt1 antibodies (these cells were assumed to be Lyt 1-2+ cells) suppressed significantly the occurrence of immune mediated OME. Findings of the present investigation suggest that T suppressor cells are regulatory T cells that suppress the occurrence of immune-mediated otitis media.
The middle ear local immune response is thought to be involved in common mucosal immune system. Recently the distibution of antigen specific IgA immunocytes which play an important role in mucosal immunity were demonstrated after middle ear stimulation. The middle ear regional lymph nodes of guinea pig may contribute to the middle ear mucosal immunity. To evaluate the contribution of regional Iymph nodes, we resected these Iymph nodes after middle ear sensitization of horseradish peroxidase. No antigen specific antibody bearomg I cells were detected in the middle ear mucosa of the animals which were resected both regional Iymph nodes. This finding suggested the contribution of regional Iymph nodes to the middle ear immune respons.
A variety of solutions were tested to find a suitable solvent of cholesteatoma debris for use in clinical practice. The specimens were taken from patients suffering from cholesteatoma during middle ear surgery and incubated in a test solution at 37°Cfor 48 hours. Hydrochloric acid (1N) and sodium hydroxide (1N) had no effect to solve the debris. Urea (1ON), acetylcysteine and trypsin had a few such effect. Proteolytic agents such as sodium dodecyl sulfat e (0.1N) and cholic acid (0.1N) had greater effect but insufficient for clinical use. In contrast, a detergent which contains interfacial active agents and a certain kind of proteolytic enzyme, such as AttackR and Hi-Top R, proved to be most effective to solve the debris.
Our previous studies have shown that cholesteatoma debris (ChD) stimulates macrophages to produce active oxygen species and a bone resorbing cytokine, tumor necrosis factor. Here we tested if ChD would induce chemotaxis of human peripheral blood monocytes, in vitro, using a microchamber technique. ChD induced migration of monocytes across Nuclepore filters. Although ChD contained lipopolysaccharides (LPS), minimal migration of monocytes to LPS was observed at concentrations of lOng to 10 μg/ml. On the other hand, 8M-urea-extracts from ChD, which consisted mainly of α-keratin, induced migratory response of monocytes, and showed a bell-shaped dose-response relation. From these results, we suggest that ChD initiates bone resorption through chemotaxis and activation of macrophages.
The keratin granulomas were observed not infrequently in the surgical specimen of a bone destructive cholesteatoma, however, it is not clearly demonstrated as to how the escaping debris induce an inflamatory process or how the keratin, one of the contents of debris, works in this process. In order to observe this process, we inplanted the porous subcutaneous chambers, which contain debris of a human cholesteatoma, LPS or gelatine, and observed histologically or immunocytochemically using RAMll after 1, 2 or 3 weeks, respectively. Highly inflammatory cell ingrowth were observed in the chember of debris 1 week after inplant. Although the cell infiltration and necrosis progressed in the debris chember after 2 and 3 weeks passed, the keratin were still observed. The keratin seems to work in prolonged or repeated inflammatory process.
At the present time, the origin of the cholesterol in the cholesteatoma is still uncertain. In this study, we cultured the tissues of cholesteatoma and added 14C-acetic acid and 3H-leucine to measure the synthesis of cholesterol in cholesteatoma in vitro. Acetic acid and leucine are one of the precursors of cholesterol synthesis. This result showed that the cholesterol derived from acetate did not exist in cholesteatoma tissue. On the other hand, the cholesterol derived from leucine exists in cholesteatoma. This result suggests that the cholesterol in cholesteatoma is synthesized in the tissue in vivo.
In this study, we examined the temporal bone histopathology of Lewis rats immunized with type II collagen under microscope. Moreover, we examined the collagenase production by fibroblasts and macrophages by culturing these cells with spleen cell conditioned medium prepared from rats immunized with type II collagen. There was no otosclerosis-like lesion in the otic capsule of rats immunized with type II collagen. Collagenase production from fibroblasts and macrophages was high, when these cells were cultured with the spleen cell conditioned medium derived from rats immunized with type II collagen.
Histological evidence of otosclerosis was found in the 7 temporal bones of 6 persons out of a total of 440 ears removed from 223 Japanese. The frequency of the histological otosclerosis was 1.59%. The area anterior to the oval window was involved in 4 ears. The area anterior internal auditory canal was involved in 1 ear. The multiple areas (semicircular canals and cochlear wall) were involved in 2 ears. Most ears had inactive foci and had no stapes fixation. We thought that the reason why the incidence of otosclerosis among Japanese was low was not only the low frequency but also the low activity of the otosclerosis foci.
The morphological changes of the fissula ante fenestram in 440 temporal bones of 222 individuals were studied. The fissula was observed in 366 bones (83.2%). The fissula orificed at the site of tympanic cavity in 81 bones, at the site of annular ligament in 78 bones and at the site of vestibule in 350 bones. There were no differences between right and left ears and no influence by aging on frequency and the site of orifice of the fissula. Otosclerotic change was also observed at any sites other than the fissula. And this confirms also the fissula does not always relate the focus of otosclerosis.
The ultrastructures of the vestibular sensory hairs were examined using rapid-freeze, freeze-substitution method. The stereocilia, which had actin filaments in it, were well preserved in this method. The glycocalyx covered the stereocilia, and was considered to play an important role in keeping position of stereocilia and bending them together. In this study, the glycocalyx appeared to be amorphous rather than fibrous. This method showed new ultrastructual findings differed from those of the conventional chemical fixation.
Development of the auditory apparatus in Bufo japonicus has been morphologically studied from early larval stages to adult stages. The table of normal development in Bufo japonicus deviced by Iwasawa was used for grouping specimens under several stages. Inner ear begins to form at the time of hatching (about stage 21-22) and is almost completed at the time of the appearance of conical hindlimbs (about St. 34-35). Formation of the operculum begins in the fenestra ovalis about the time when toes begin to develop (about St. 37) and is finished at the time when hindlimbs begin to move (about St. 41). About stage 41, the columella has began to form. By about 7 days after the first terrestrial activity, middle ear components such as columella, plectrum, middle ear cavity and tympanic membrane are formed.
The embryonic development of the inner ear of the guinea pig was investigated by immunohistological methods. The 33-35th, 37-39th, and 44-46th gestational day guinea pigs, which had been administrated bromodeoxyuridine (BrdU) in their mother, was collected. In every gestational day BrdU labeling cells were not detected in the epitherial layer facing the endolymph. This result and ultramorphological study show that these epitherial layer finished the stage of the cell division and was in the differentiation stage.
The amount of melanin in the stria vascularis was computed, using three type of hamsters was found to be different in the color of coat and iris. The amount of melanin contained in the intermediate cells correlates with the degree of pigmentation in the animal's coat and eyes. Wild type of the hamster were found to dendritic melanocytes beside the basal cell. But the dendritic melanocytes were not found in TPB or MP. Thus, the melanocyte of the inner ear is controlled by genotype P, (pink eye dilution). In the heterochromia of iris, the amount of melanin in stria vascularis tends to increase, in proportion to the amount of the melanin in iris.
The basement membrane of the otocyst on the 5-day-old chick embryo was positive to laminin. On the 9-day-old chick embryo, the basement membrane of the macula of the saccule and utricle was positive, but the crista ampullaris was positive very weakly. The basement membrane of the endolymphatic sac on the 11-day-old chick embryo was very strongly positive. These results suggest that laminin may be an essential substance for considering the pathology of the vestibular endorgans. The uneven distribution of laminin suggests that the basement membrane has some important function of the inner ear.
The serial sections of the statocysts of the four kinds of the decapoda and two kinds of the decapoda, were observed with the 10% folmalin diluted with seawater as soon as possible after fishing with a line. They were dehydrated with ethylalcohol diluted with distiled water and seawater, then embedded in celloidin. The sections were cut 30 μm and staind with hematoxylin and eosin. As a result, we could get good specimen of the macula statica, crista statica, processes, statolith, macula, crista nerves and membranous wall.
Vestibular effects of barotrauma were studied by morphological methods using SEM in guinea pigs. The animals were placed in a high pressure chamber and the pressure increased from 1 ATA to 2 ATA in 10 minutes, maintained at 2 ATA for 10 minutes before reducing the pressure to 1 ATA in 1 minute. Stereomicroscopy showed round window membrane rupture in most of the animals; the outstanding SEM change was a slight hair cell damage in the crista ampullaris area. Disruption and disappearance of hairs of sensory cells in the crista were observed immediately following the sudden reduction of pressure. After 2 weeks, a few supporting cells replaced the damaged hair cells in the crista.
An argon laser was used to irradiate the otolithic organs of guinea pigs. Two different argon laser devices were used. One was attached to a surgical microscope. The other was a device with a hand piece. The wave length (488 nm and 514 nm), power (1.5w), and irradiation time (0.5sesc) were the same. After stapedectomy, the argon laser irradiated the otolithic organ without touching the sensory organs. Animals were sacrificed immediately or after 1, 2, 4 and 10 weeks for morphological studies. Sensory cells and supporting cells were elevated from the basilar membrane at the irradiated area. The otolith of the macula had disappeared after 2 weeks. The sensory epithelium degenerated into one layer of cuboidal cells, also in 2 weeks. At 10 weeks the entire macula had disappeared.