Age-Dependent Calcium-Binding Protein Expression in the Spiral Ganglion and Hearing Performance of C57BL/6J and 129/SvJ Mice.

BACKGROUND/AIMS: Calcium-binding proteins in neurons buffer intracellular free Ca2+ ions, which interact with proteins controlling enzymatic and ion channel activity. The heterogeneous distribution of calretinin, calbindin, and parvalbumin influences calcium homeostasis, and calcium-related neuronal processes play an important role in neuronal aging and degeneration. This study evaluated age-related changes in calretinin, calbindin, and parvalbumin immune reactivity in spiral ganglion cells. METHODS: A total of 16 C57BL/6J and 16 129/SvJ mice at different ages (2, 4, 7, and 12 months) were included in the study. Hearing thresholds were assessed using auditory brainstem response before inner ears were excised for further evaluation. Semiquantitative immunohistochemistry for the aforementioned calcium-binding proteins was performed at the cellular level. RESULTS: The hearing thresholds of C57BL/6J and 129/SvJ mice increased significantly by 7 months of age. The average immune reactivity of calbin-din as well as the relative number of positive cells increased significantly with aging, but no significant alterations in calretinin or parvalbumin were observed. CONCLUSIONS: Upregulation of calbindin could serve as a protection to compensate for functional deficits that occur with aging. Expression of both calretinin and parvalbumin seem to be stabilizing factors in murine inner ears up to the age of 12 months in C57BL/6J and 129/SvJ mice.

Pepsin and oropharyngeal pH monitoring to diagnose patients with laryngopharyngeal reflux.

OBJECTIVES: The aim of this study was to compare the diagnostic accuracy of salivary pepsin with oropharyngeal pH monitoring using the Restech measurement system (Dx-pH) for the diagnosis of laryngopharyngeal reflux (LPR). STUDY DESIGN: Prospective cohort study. METHODS: Seventy patients with primary symptoms related to LPR underwent gastroscopy, high-resolution manometry, pH throughout 24-hour monitoring (MII-pH), and barium esophagography between October 2015 and May 2018. In addition, an ear, nose, and throat examination was performed, including assessment of Belafsky Reflux Finding Score (RFS). Clinical symptoms were evaluated with the Belafsky Reflux Symptom Index (RSI) and the Gastrointestinal Quality of Life Index (GIQLI). Simultaneous to MII-pH, pepsin determination and Dx-pH were performed. RESULTS: Of 70 patients, 41 (58.6%) subjects with a pathological DeMeester score showed higher mean values of pepsin (mean value: 216 ng/mL, 95% confidence interval [CI]: 172 to 260), compared to patients with a normal DeMeester score (mean value: 161 ng/mL, 95% CI: 115 to 207). Salivary pepsin showed a specificity of 86.2% and sensitivity of 41.5% for diagnosing LPR using the optimal cutoff value of 216 ng/mL. Furthermore, a significant correlation between the values of salivary pepsin and the RSI score was seen in patients with pathological results in MII-pH (r = 0.344; P = 0.046). However, elevated Dx-pH measurements showed no significant correlation with either MII-pH, RSI score, RFS score, or GIQLI score, or with the results of pepsin measurement. CONCLUSION: Pepsin measurement in saliva could be an alternative tool to assist office-based diagnosis of LPR, whereas Dx-pH does not seem to be an adequate test. LEVEL OF EVIDENCE: 2B Laryngoscope, 130:1780-1786, 2020.