Recurrent hearing impairment and nystagmus induced by repeated antigen exposure in actively sensitized guinea pigs

Degranulation of Murine Resident Cochlear Mast Cells: A Possible Factor Contributing to Cisplatin-Induced Ototoxicity and Neurotoxicity

Permanent hearing loss is one of cisplatin's adverse effects, affecting 30-60% of cancer patients treated with that drug. Our research group recently identified resident mast cells in rodents' cochleae and observed that the number of mast cells changed upon adding cisplatin to cochlear explants. Here, we followed that observation and found that the murine cochlear mast cells degranulate in response to cisplatin and that the mast cell stabilizer cromoglicic acid (cromolyn) inhibits this process. Additionally, cromolyn significantly prevented cisplatin-induced loss of auditory hair cells and spiral ganglion neurons. Our study provides the first evidence for the possible mast cell participation in cisplatin-induced damage to the inner ear.

Chronic diseases and life events accounted for 2-18 % population attributable risks for adult hearing loss: UK Adult Psychiatric Morbidity Survey, 2007

Links between chronic diseases and hearing loss in adults have emerged. However, previous investigations were not complete, and the role of life events was unclear. Therefore, it was aimed to examine the relationships of common chronic diseases and life events and adult hearing loss in a country-wide and population-based study. Data were retrieved from UK Adult Psychiatric Morbidity Survey, 2007, being cross-sectional, including demographics, self-reported prior health conditions and hearing loss (ever and in the last 12 months), and several major life events. Analyses included Chi square test, t test, logistic regression model, and population attributable risk estimation. People who had prior health conditions including cancer, migraine, dementia, depression, cataracts, chronic bronchitis, allergy, bowel problem, bladder problem, arthritis, muscle problem or skin problem tended to report hearing loss than their counterparts. People who have experienced major life events including post-traumatic stress disorder, serious illness of close relatives, death of family, serious problems with friends, major financial crisis, valuables stolen, being bullied, violence at home, sexual abuse or running away from home were also more likely to experience ever hearing loss problem or that in the last 12 months. 2.0-13.1 % adult hearing loss could be delayed or prevented by managing chronic diseases while 4.1-18.1 % might be delayed or prevented by minimizing the negative effects of life events. Chronic diseases and life events were associated with hearing loss in adults. Better managing lifestyle to minimize detrimental impacts in future health and nursing programs would be suggested.

Chronic cerebrospinal venous insufficiency in Ménière disease

Objectives

The aim of this study was to focus on patients suffering from cochleo-vestibular disorder with and without Ménière disease (MD) in order to verify whether chronic cerebrospinal drainage abnormalities could play a role in the etiopathogenesis of endolymphatic hydrops.

Methods

Fifty-two volunteers were enrolled and subdivided into two groups: 24 definite MD and 28 not-MD. Both magnetic resonance venography imaging with contrast-enhanced imaging of the venous cerebrospinal system (MRV) and venous echo-color Doppler (ECD) were performed.

Results

MRV showed abnormalities in 83% of MD and 57% of not-MD subjects ( p < 0.001). Asymmetrical cervical venous flow, assessed by MRV, was confirmed by ECD in 62.5% of MD but in only 21.5% of not-MD subjects ( p<0.001).

Conclusion

Chronic cerebrospinal venous insufficiency might be the anatomical background, which provides a predisposing factor for the development of endolymphatic hydrops in MD patients.

PAF- and histamine-receptor antagonists lessen allergen-induced hearing impairment in guinea pigs

We have demonstrated degranulation of mast cells in the endolymphatic sac as well as an increase in audiological threshold shift in the experimental animal models following antigen provocation. Mast cells, however, release such chemical mediators as histamine, platelet activating factor (PAF), and leukotriene due to an antigen-antibody reaction on the cell surface. The aim of this study was to clarify the major chemical mediators responsible for hearing impairment in the animal models following antigen provocation. Guinea pigs were actively sensitized with DNP-Ascaris and provoked with an injection of DNP-BSA. A significant audiological threshold shift was observed at 1, 10, 24, and 72 h following challenge with allergen. The peak shift was at 10 h; all changes were reversed after 7 days. This threshold shift was abolished by prior injection of either a histamine- or PAF-receptor antagonist to allergen, but not of a leukotriene-receptor antagonist. Results suggest that histamine and PAF are involved in the hearing impairment induced by allergen exposure in the guinea pig.