Search

To evaluate the effect of nitric oxide synthase (NOS) and nitric oxide(NO) on sensorineural hearing loss (SNHL) secondary to secretory otitis media (SOM).Samples of middle ear effusion were collected at the time of tympanocentesis from 16 cases of SOM with SNHL(group A) and 16 cases of SOM without SNHL(group B). And the concentration of NO and NOS activity in middle ear effusion were detected by colorimetric assay (Griess method).The concentration of NO in group A (181.19 +/- 44.31) micromol/L was significantly higher than that in group B (137.00 +/- 40.67) micromol/L (P0.01). The NOS activity in group A (97.69 +/- 29.62)U was also significantly higher than that in group B (75.50 +/- 26.99)U (P0.05).Excess generation of NO in middle ear effusion which synthesized by NOS may hurt inner ear directly by its cytotoxic action or enhance local inflammatory reaction with other inflammatory factors. This study suggests that NO play a significant role in the process and pathogenesis of SNHL secondary to SOM.

To confirm whether systemic hypotension influences the genesis of sudden sensorineural deafness(SSD) in young people.Twenty-eight untreated young patients diagnosed as SSD in experimental group were compared with 30 age- and sex- matched subjects in control group. Both groups have received the clinic BP testing, 24 hour BP monitoring and their indexes about lipid metabolism were examined and recorded. The statistical analysis was carried out on the data obtained from 2 groups.The average clinic and 24 hour BP values in patients with SSD were significantly lower. The hypotension (diagnosed according to ISD standard) occurred more frequently in SSD group. There was no difference in metabolism indexes between 2 groups.Systemic hypotension which can cause perfusion damage in cochlea can be considered as a possible cause responsible for the development of SSD in young subjects. It's necessary to keep blood pressure monitoring and avoid applying vasodilating drugs until a suspecting or known hypotensive condition is associated with hearing loss.