Leiomyoma of the parapharyngeal space.

A rare case of leiomyoma of the prestyloid parapharyngeal space is reported together with computed tomographic and magnetic resonance imaging findings. The tumor appeared as a well-circumscribed ovoid mass with some calcifications and lobulations. Because the attenuation, signal intensity, and shape of the mass were not specific and were similar to those of a pleomorhic adenoma, the most common tumor of the prestyloid parapharyngeal space, radiological differentiation of leiomyoma from pleomorphic adenoma of the prestyloid parapharyngeal space was difficult.

Adenoid cystic carcinoma of the external auditory canal: correlation between histological features and MRI appearances.

A rare case of adenoid cystic carcinoma of the external auditory canal with magnetic resonance imaging appearances is reported. Both T1 weighted and T2 weighted MR images showed the tumour as a hypointense mass, although there was marked contrast enhancement. Microscopic examination of the resected tumour showed a preponderance of solid tumour cell nests. According to previous reports, these pathological and radiological findings indicate a poor prognosis.

Study on adhesion factors in lymphocyte migration to the middle ear mucosa.

We investigated influences of adhesion factors on the migration of antigen-specific IgA-forming cells (ASAFCs) to the middle ear mucosa by means of an in vitro lymphocyte binding assay. Peyer's patch (PP) lymphocytes from guinea pigs with mucosal immunization, which are rich in ASAFCs, more frequently bound with the inflamed middle ear mucosa than those of PP and spleen cells from animals with systemic immunization, in which antigen-specific IgG-forming cells (ASGFCs) were induced (p > .001). The bindings were not affected by antigenic and nonantigenic stimuli to the middle ear mucosa for producing otitis media. On human middle ear mucosa from 10 patients with acute mastoiditis and chronic otitis media, endothelial cells of newly grown vessels were stained strongly with intercellular adhesion molecule (ICAM)-1, and weakly with vascular cell adhesion molecule (VCAM)-1, platelet endothelial cell adhesion molecule (PECAM), and endothelial leukocyte adhesion molecule (ELAM)-1. Many lymphocytes bound mainly to these endothelial cells, and a few cells were observed bound to the basal portion of epithelial cells. The binding of lymphocytes was significantly, but not completely, inhibited by anti-ICAM-1 antibody (p < .001). These findings suggest that PP lymphocytes with activated mucosal immunity more frequently migrate to the inflamed middle ear mucosa, and that those migrations, after extravasation, may be regulated by the interaction between various binding factors and their receptors on lymphocytes, which is different from that of adhesion molecules and their ligands in the extravasation.

Lymphocyte migration to the middle ear mucosa.

We investigated the migration of antigen-specific IgA-forming cells to the middle ear mucosa. Antigen-specific lymphocytes of IgA and IgG classes were induced in guinea pigs according to an immunization strategy previously described. From those animals, chromium 51-labeled lymphocytes of Peyer's patches and spleen were transferred to radiated chimera recipients. The radioactivity levels of the middle ears with antigenic and nonantigenic stimuli were significantly higher than those of the control ears (p < .05). Those levels of radioactivity were influenced neither by origins and subsets of transferred cells nor by antigenic stimuli to the mucosa (p > .05). Many labeled cells were observed in the middle ear effusion, while few were found in the inflamed mucosa. These findings suggest that in the early stage of inflammation, lymphocytes, including antigen-specific T and B cells, may be recruited from the blood circulation to the inflamed middle ear mucosa by nonspecific inflammatory processes that may mask antigen-specific factors in lymphocyte migration.

Lymphocyte-mucosal interaction of the middle ear mucosa.

The middle ear mucosa possesses immunologic features similar to those of the peripheral mucosa sites in the common mucosal immune system and after mucosal immunization, antigenspecific IgA-forming cells appear in the inflamed mucosa of the tympanic cavity. Recent investigations suggest that lymphocyte migration to lymphoid tissues is regulated by lymphocyte-high endothelial venules (HEV) interaction. However, the lymphocyte migration mechanism to the middle ear mucosa is still unclear. We investigated whether or not organ-specific determinants which lymphocytes bind with are present on the middle ear mucosa by in vivo and in vitro lymphocyte adherence assays by using fluorescein-labeled lymphocytes from various lymphoid tissues. Many lymphocytes from Peyer's patches and hilar lymphnodes adhered on the inflamed middle ear mucosa with or without mucosal immunization, while these cells were not found on the normal tympanic mucosa. The number of the cells was smaller than that in the gastrointestinal mucosa. Lymphocyte adherence to the middle ear mucosa was not suppressed by anti-T cell antibody. These findings suggest that the middle ear mucosa possesses organ-specific mucosal determinants which B-lymphocytes selectively bind with, and that those determinants which regulate lymphocyte migration to the middle ear mucosa differ from those of other mucosae in the gastrointestinal tract.

Oral vaccine therapy for pneumococcal otitis media in an animal model.

We investigated whether mucosal IgA response in the middle ear cavity against Streptococcus pneumoniae type 19F is enhanced by use of enteric capsules, and whether the resulting mucosal immunity can prevent pneumococcal otitis media. Adult Hartley guinea pigs were employed. With intratympanic inoculation of 10(5) and 10(6) live S pneumoniae, the occurrence of pneumococcal otitis media significantly decreased in guinea pigs that received intraduodenal and intragastric immunization by enteric capsules. In these guinea pigs, the values of salivary IgA antibody titers against S pneumoniae were significantly greater, and histologic changes of the middle ear mucosa were also slighter than those of control guinea pigs. These findings indicate that oral vaccination by enteric capsules elicits mucosal IgA responses, as well as intraduodenal immunization, to prevent pneumococcal otitis media. These results suggest the possibility of clinical application of oral vaccination by enteric capsules for the prevention of middle ear infection.