Fumiko Tanimura

Experimental otitis media with effusion induced by intratympanic lipid A instillation

Otitis media with effusion was induced in guinea pigs by intratympanic instillation of lipid A, the lipid moiety of gram-negative bacterial lipopolysaccharide from Salmonella minnesota Re595. Lipid A was chosen as an inducer because of its similar composition among various bacterial species. Animals were killed from the first to 14th day after instillation of various concentrations (0.2, 2, 20, 200 micrograms/ml) of lipid A in 0.5% triethylamine. By 3 days after instillation, all experimental animals developed serous middle ear effusion. The histologic findings included hemorrhage, mucosal edema, capillary engorgement, and migration of infiltrative cells including macrophages, polymorphonuclear neutrophils, and lymphocytes. These findings were most prominent 3 days after instillation, and the recovery of the middle ear epithelium was observed within 14 days. Repeated instillation of lipid A (2 micrograms/ml) at an interval of 14 days reinforced the local response accompanied by serous middle ear effusion. These findings indicate that lipid A can induce the inflammatory changes with middle ear effusion and that lipid A plays an important role in the pathogenesis of otitis media with effusion.

Cupulogenesis and glycoconjugates in the labyrinthine ampulla as revealed by WGA-gold labeling

SummaryWe studied the distribution of wheat germ agglutinin (WGA)-bindable glycoconjugates in the vestibular ampulla of mongolian gerbils. WGA was conjugated with gold particles and applied to Lowicryl K4M sections of the ampulla. WGA-binding sites were found on the cupula and some of the secretory granules and Golgi apparatuses in the supporting cells of the sensory epithelia. The granules were seen to secrete into the endolymphatic space through reticular membrane. It is likely, therefore, that glycoconjugates are glycosylated at the Golgi apparatus in the supporting cells, stored in the granules, and secreted through the reticular membrane into the endolymphatic space to be used as a component of the cupula. The cell membranes of various cells, connective tissue filaments in the perilymphatic space and the cytoplasm of melanocytes were also labeled with WGA-gold.

Lysozyme producers in nasal mucosa. An immunocytochemical study.

The question of whether or not goblet cells in the nasal mucosa are lysozyme producers has yet to be examined. In the present study, lysozyme was localized by the protein A-gold technique in human nasal mucosa with special attention to goblet cells. Both light and electron microscopic immunostaining revealed lysozyme in the secretory granules of the goblet cells, although far less than the amount present in the serous cells of the nasal glands. We concluded that the nasal glands were the main producer and goblet cells the subsidiary producer of lysozyme in nasal mucosa.

Teratoma of the soft palate with multifocal cyst formation in the tongue and the brain.

SummaryWe report a case of a solid and cystic teratoma appearing in the soft palate that was associated with a cyst in the tongue and a huge cystic formation in the arachnoid of the brain. Histologically, the tumor of the soft palate contained elements of all three germ layers, with a predominance of mature glial tissues. This typical teratoma and the two other concurrent lesions were all located on the same side of the head, and were thought to have a common embryonic origin. These multifocal tumors may represent an incomplete manifestation of a “teratoma complex”.

Amylase secretion by nasal glands. An immunocytochemical study.

Amylase, an enzyme that hydrolyzes starch, has been localized in the nasal mucosa for the first time by the protein A-gold technique. The amylase appeared to be produced by serous cells of the nasal glands. This enzyme has the potential for use as a tumor marker for cancer of the nasal cavity. The function of amylase in the physiology of nasal secretions is discussed.

Glycoconjugate histochemistry in the glycocalyx of guinea pig middle ear mucosa.

SummaryAn attempt was made to determine the composition of oligosaccharide side chains in the apical cell surface glycocalices of the middle ear epithelium. This glycoconjugate is located on the innermost luminal surface, but its function is still unknown. The lectins evaluated included Triticum vulgare, Canavalia ensiformis, Maclura pomifera, Arachis hypogaea, Ricinus communis I (RCA-I), and Limax flavus. The staining results obtained with the six different lectin probes in the Lowicryl K4M-embedded guinea pig middle ear mucosa suggest that the glycocalyx contains β-d-N-acetylglucosamine, sialic acid, and β-d-galactose in the major carbohydrate moiety. The present study also indicates that a polarity exists on the cell surfaces in the distribution pattern of the carbohydrate component, especially those of β-galactosyl residues, as revealed by RCA-I binding. This may imply functional separation of the epithelial cells.

Experimental immune complex otitis media: localization of IgG by protein A-gold technique.

Immune complex (IC) was made of bovine serum albumin (BSA) and anti-BSA guinea pig serum, and instilled into the tubotympanic cavity of untreated guinea pigs. The location of IgG was determined by using the protein A-gold technique to trace IC in the tubotympanic mucosa of the otitis media with effusion (OME) caused by the instillation. IgG was found on the effusion, degenerated ciliated cells and on granules of goblet cells. There was no evidence of intense accumulation of IgG on the basement membrane of the mucosal epithelium or the capillaries. It is likely that IC activates complements in the tubotympanic cavity to cause OME.

Cell-surface glycoconjugate layer in the tubotympanic mucosa of the guinea pig as revealed by wheat germ agglutinin/gold labelling.

To evaluate the protective function of the mucous blanket (MB) against lectin substances, we examined at the ultrastructural level whether intraluminal colloidal gold-labelled wheat germ agglutinin (WGA) could enter the MB-covered epithelial cell surface of the guinea pig tubotympanic mucosa. Post-embedding staining with WGA/gold on thin tissue sections was done in parallel for comparison. The cell surface glycoconjugate of the eustachian tubal and transitional epithelium had a typical bilayered structure: the outer MB and the microvilli-associated glycocalyx (MAG), which were interposed by the interciliary fluid zone. In squamous epithelium of the distal middle ear, the MB adhered to the MAG, thereby forming a monolayered coat of glycoconjugates at the cell surface. In the pre-embedding staining, WGA/gold did not bind with the MB and MAG in the eustachian tube, and exclusively bound with MB in the transitional area. Direct binding was also found with MAG and the apical plasmic membrane in the squamous epithelium. These findings indicate that MAG is occluded by MB lined with the interciliary fluid zone for luminal access of lectin at the proximal lumina of the tubotympanic epithelium. It is also suggested that MB existing at two sites possesses a different WGA-binding capacity: shielding as a “dust cover” in the eustachian tube and entrapping as a “flypaper” against lectin in the transitional area of the middle ear.