Tissue eosinophilia in chronic sinusitis: quantification techniques.

OBJECTIVE: To ascertain the reliability of a proposed method for quantifying tissue eosinophilia in sinus mucosa. DESIGN: Prospective cohort study. INTERVENTIONS AND OUTCOME MEASURES: Pathology slides from patients undergoing endoscopic sinus surgery for chronic rhinosinusitis were independently assessed by 2 reviewers. Using a proposed systematic counting method, the degree of tissue eosinophilia was quantified. Disease severity was assessed by computed tomographic (CT) staging. Intrarater, interrater, and intrapatient reliability was determined using correlational reliability analysis. The degree of correlation between tissue eosinophilia and CT stage was determined. RESULTS: One hundred thirty-two slides from 65 patients were reviewed. The mean (SD) eosinophil density was 23.4 (37.2) eosinophils per high-power field. Only 12 patients (18%) had no eosinophils on histopathologic analysis. Strong intrarater (r> or =0.91 for each rater, P<.001) and interrater reliability (r> or =0.82 between raters, P<.001) was noted for the quantification method. A moderate degree of correlation was found between CT scan stage and degree of tissue eosinophilia (Spearman rho = 0.62, P<.001). CONCLUSIONS: The proposed method for quantifying tissue eosinophilia in sinus mucosa is reliable and valid. A relatively strong correlation exists between CT scan stage and tissue eosinophilia in chronic rhinosinusitis.

Innervation of supporting cells in the apical turns of the guinea pig cochlea is from type II afferent fibers.

The outer supporting cells in the apical turns of the guinea pig cochlea receive a dense innervation. Our previous study (Fechner et al. [1998] J. Comp. Neurol. 400:299-300) suggested that this innervation of the Deiters' and Hensen's supporting cells was not derived from efferent fibers of the olivocochlear bundle, but its origin has not been further specified. To test the hypothesis that the innervation was afferent in origin, we traced apical afferent fibers that were retrogradely labeled by extracellular injections of horseradish peroxidase. Labeled afferent fibers were of two types: type I fibers contacted inner hair cells, whereas type II fibers crossed the tunnel and contacted outer hair cells. Significantly, most of the type II fibers also formed branches to the outer supporting cells. Although a few olivocochlear efferent fibers formed such branches, counts indicated that the overwhelming majority of the branches were produced by type II afferent fibers. These branches were not produced by basal type II fibers. Apical type II fibers also differed from basal fibers by having shorter lengths, spiraling both apically and basally, and contacting all three rows of outer hair cells. These innervation differences suggest differences in the ways that information from outer hair cells is processed in the apex versus the base of the cochlea.

Dense innervation of Deiters' and Hensen's cells persists after chronic deefferentation of guinea pig cochleas.

Innervation of Deiters' and Hensen's cells has been described in the organ of Corti of several mammalian species and has been suggested to arise from the olivocochlear (OC) efferent system (Wright and Preston [1976] Acta Otolaryngol. 82:41-47). In the present study, antineurofilament immunostaining was used to reveal these outer supporting cell fibers (OSCFs) in the normal guinea pig. In control ears, OSCFs were absent in the basal half of the cochlea but increased in number steadily toward the apex, peaking at values of over 1,200 fibers/mm. These values indicate a far more profuse innervation of supporting cells than has been described previously, suggesting that most OSCFs were not stained in previous immunohistochemical studies. Chronic cochlear deefferentation was used to test whether OSCFs are part of the OC system. The OC bundle was transected unilaterally, and the animals were allowed to survive for 4-8 weeks. Completeness of deefferentation was assessed by using acetylcholinesterase staining of the brainstem and measurement of the density of OC fascicles in the cochlea. By using these metrics, unilateral deefferentation was nearly complete in three animals. In successfully deefferented cases, the OSCF innervation density was not statistically different from control values. We conclude that the vast majority of OSCFs are not of OC origin. We speculate that they may be branches of type II afferent fibers to outer hair cells and that a smaller population of OSCFs with different morphology and immunoreactivity may arise from the OC system.