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.

Animals↗

PubMedDate not supplied

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.

Adult↗

PubMedDate not supplied

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.

Adult↗

PubMedDate not supplied

Quantitative analysis of kanamycin ototoxicosis.

The morphological changes after kanamycin intoxication of the inner ear, including both the cochlea and the vestibule, were quantitatively analysed by the surface preparation technique after succinic dehydrogenase staining. 75 guinea pigs were used. The outer hair cells in the basal coil and the inner hair cells in the upper coils of the cochlea were the most severely damaged, but many unusual modes of damage were also revealed. For example, the initial hair cell damage in the cochlea appeared in the upper hair cells. The clearly observed vestibular damage contradicts the general belief that kanamycin is not so toxic to the vestibular hair cells. The utricular macula and the lateral crista were most severely damaged. The delayed ototoxicity of kanamycin was observed for the first time in the vestibular hair cells.

Animals↗

PubMedDate not supplied

Ultrastructural and fluorescence histochemical studies on the sympathetic innervation of the canine laryngeal glands.

The existence of the adrenergic terminals of the canine laryngeal glands has been revealed by electron microscopy and fluorescence histochemistry. Adrenergic fibres with fluorescent varicosities were observed around the base of th acini in the submucosa. In dogs treated with 5-OHDA, varicosities containing both small and large, dense-cored vesicles containing both small and large, dense-cored vesicles, believed to be adrenergic terminals, were found near blood vessels, gland cells and myoepithelial cells in the submucosal gland region. The role of these adrenergic terminals is briefly discussed.

Adrenergic Fibers↗

PubMedDate not supplied

The site of involvement of hypertension within the cochlea. A comparative study of normotensive and spontaneously hypertensive rats.

The function and morphology of the cochlea of the spontaneously hypertensive rat (SHR) were examined and compared with the age-paired normotensive Wistar Kyoto rat (WKY). Electro- cochleographic study revealed that the function of the cochlea in the SHR declined with increasing age to a greater extent than that of WKY. Electronmicroscopic study revealed that the primary site of the cochlear deterioration of the SHR was the vascular stria, followed by the organ of Corti. Some hypotheses to explain this phenomenon are proposed for further study.

Aging↗

PubMedDate not supplied

Substance P nerve fibres in the canine larynx by PAP immunohistochemistry.

The distribution of the Substance P (SP) immunoreactive nerve fibres in the canine larynx and laryngeal nerves was studied by PAP immunohistochemistry. Many individual SP immunoreactive nerve fibres with varicosities were observed within the epithelial layer and in the connective tissue below the epithelium of the laryngeal mucosa. Small numbers of SP immunoreactive nerve fibres were also found in the submucosal gland region and some of them appeared to terminate in glandular cells. These findings are consistent with the view that SP might be involved in the laryngeal sensory innervation system and the laryngeal glandular secretion. No SP immunoreactive nerve fibres were found in any intrinsic laryngeal muscles. The recurrent laryngeal nerve and the superior laryngeal nerve contained SP immunoreactive nerve fibres and were considered to lie in the pathway of the SP nerve fibres to the larynx.

Animals↗