Effects of long-term azithromycin therapy on auditory functions in children with chronic respiratory diseases.

BACKGROUND AND OBJECTIVES: In recent years, long-term azithromycin (AZT) use has been increased in pediatric patients with chronic respiratory tract problems. In this study, we aimed to assess auditory functions in children on long-term AZT therapy. METHOD: The study included 43 patients who received long-term AZT treatment and 27 age-matched, healthy controls. In the study and control groups, ear-nose-throat examination, pure tone audiometry, speech recognition threshold (SRT), speech discrimination score (SDS), uncomfortable loudness level (UCL), acoustic reflex tests, and otoacoustic emission tests were performed. The test results were statistically compared between groups. RESULTS: Mean age was 11.3 ± 0.56 years in the study group and 9.3 ± 3.07 years in the control group. The medain hearing examination was 8 months after end of AZT treatment (Ranged: 1-12 months). No significant difference was found in normal- and high-frequency audiogram tests at any frequency between study and control groups. Also, no significant difference was found in distortion product otoacoustic emissions (DPOAE) and transient evoked otoacoustic emissions (TEOAE) tests between groups. Also, there was no significant difference in acoustic reflex, SRT, SDS, and UCL test results between study and control groups. CONCLUSION: This is the first study assessing auditory functions comprehensively in pediatric patients who received long-term AZT therapy. In this study, it was shown that long-term AZT use had no deleterious effect on auditory function tests.

Therapeutic effects of metformin for noise induced hearing loss.

OBJECTIVE: This study aimed to investigate the healing effect of metformin on noise induced hearing loss (NIHL) by measuring audiological, biochemical and histological parameters. MATERIALS AND METHODS: 32 rats were divided into four groups (Group 1: Noise, Group 2: Noise + Metformin, Grup 3: Metformin, Grup 4: Control). Broadband noise was applied to Group 1 and Group 2 after basal measurements. Measuring audiological (distortion product otoacoustic emission (DPOAE) and Auditory Brainstem Response (ABR)), biochemical (total antioxidant status (TAS), total oxidant status (TOS), oxidative status index (OSI), DNA damage, IL-1 beta, IL-6, TNF alfa, HSF-1 and COX-2) and histological parameters. RESULTS: Group 2 had significant decreases in ABR thresholds on day 7 and day 14 compared to day 1. DPOAE values of Group 2 on the 7th and 14th days were significantly higher than the post-noise levels. DNA damage, TOS and OSI values of Group 1 were significantly higher than the other groups. The Cox-2 value of Group 1 was higher than all other groups. The HSF-1 value of Group 2 was significantly higher than that of Group 1. In terms of IL-1 Beta, IL-6 and TNF-alpha values, there was no significant difference between groups 2, 3 and 4 and these values were significantly lower than group 1. In histopathological results of our study, no significant difference was found between the groups being exposed to noise and the control group. CONCLUSION: This study showed that early period of Metformin treatment has therapeutic effect on NIHL.

Different concentrations of mesna application have an effect on the internal ear?

OBJECTIVE: The use of Mesna as a chemical dissector in higher concentrations may reduce the length of time of operation by providing more effective dissection as well as being used in otologic pathologies such as tympanosclerosis. In this study, it was aimed to assess the effect of Mesna on the internal ear, which was applied intra-tympanically in higher concentrations than the conventional use. METHODS: Twenty-four female rats were included in our study. The rats were randomly divided into three groups (Group 1: Mesna 50%, Group 2: Mesna 100%, Group 3: Saline). At the beginning of the study, DPOAE and ABR measurements were carried out on every rat on days 7 and 14. At the end of the study, cochleas of the rats were excised and histopathological assessments were carried out. RESULTS: Basal values and DPOAE and ABR values on day 7 and 14 of Group 1, Group 2, and Group 3 were similar to each other. No significant difference was detected among the three groups in the histopathological assessment carried out at the end of the study. CONCLUSION: It was revealed by audiological and histopathological parameters that the use of Mesna at 50% and 100% concentrations did not create toxicity effects on the internal ear. Mesna would be more effective by being used in higher concentrations in audiological surgeries, that its duration of operation world reduce and could being used in different indications including tympanosclerosis.

Evaluation of the protective effect of Botulinum toxin type A injection on otitis media with effusion.

OBJECTIVE: This study makes an analysis of the effect of Botulinum toxin type A on otitis media with effusion in rats. METHOD: As part of the study, 24 male Wistar Albino rats were divided into three groups: Group 1: Botulinum toxin Type A and Histamine (intratympanic 0.2 ml = 20 unit BTA); Group 2: Saline and Histamine (intratympanic 0.2 ml 0.9%); Group 3: Histamine (intratympanic 0.2 ml). Histamine (intratympanic 0.2 ml) was administered into the right ear for all groups. DPOAE and ABR tests were carried out on days 5, 10, 15 and 20 from the beginning of the study. RESULTS: There was no significant difference between DPOAE and ABR scores of the groups. In each group, the DPOAE scores for the right ear significantly decreased on day 5 when compared to the basal scores. In each group, there was no significant difference between days 5, 10 and 15 for the right ear. CONCLUSIONS: Botulinum toxin type A blocked the secretion of glands in the middle ear and showed no effect to prevent the formation of serous otitis. In addition, it was found out that Botulinum toxin did not lead to any morphological change in the cochlea.

Dose and time dependent ototoxicity of aspartame in rats.

CONCLUSION: Low-dose administration of Aspartame (Ap) did not produce a significant ototoxic effect at the end of the 6th month. However, duration of the ototoxic effect is shortened and severity of the effect is increased as dose and duration of Ap administration is increased. OBJECTIVES: While Ap toxicity has been studied in short- and long-term studies, its effects on hearing have not been investigated. This study was conducted to evaluate the effects of long-term consumption of Ap administered in various doses on hearing status of rats. METHODS: The study included 54 female Wistar Albino rats. Ap was given for 6 months to the rats. The groups were assigned according to levels of Ap dosage. DPOAE and ABR tests were utilized for serial hearing evaluations. Serial hearing measurement times were designed as baseline, 1st week, 2nd week, 1st, 2nd, 3rd, and 6th months. RESULTS: While audiological parameters deteriorated with 100 mg/kg/day dose after the 3rd month, ABR thresholds were elevated and DPOAE values were significantly decreased in 500 mg/kg/day and 1000 mg/kg/day applications after the 2nd month. In 2000 mg/kg/day and 4000 mg/kg/day applications, deteriorations in audiological parameters were detected as early as the first and second months; respectively.

Does systemic steroid deficiency affect inner ear functions?

PURPOSE: Today corticosteroids are employed for the treatment of various inner ear disorders. In this study we have investigated probable changes in hearing functions resulting from a deficiency of systemic steroid secretions. MATERIALS AND METHODS: Twenty four healthy female rats were used in our study, allocated into three groups (medical adrenalectomy, medical adrenalectomy+dexamethasone, no treatment). Audiological evaluations were conducted at the beginning of the study and on days 7, 14 and 21. Blood samples were taken at the beginning and at the end of the study and blood corticosterone levels were determined. RESULTS: While there were no significant differences between the basal, 7th, 14th and 21st day DPOAE values of group 1, their ABR threshold values showed significant increases. In group 2, there were no significant differences between the basal, 7th, 14th and 21st day DPOAE values. ABR thresholds of group 2 showed significant increases on days 7 and 14 as compared to their basal values, but there were no significant differences between the 21st day and basal ABR threshold values. There were no significant differences between the basal cortisol levels of the three groups. The mean cortisol level of group 1 on day 21 was found to be significantly lower than those of groups 2 and 3. CONCLUSION: The results of the study demonstrated that there were no significant changes in DPOAE values with the cessation of cortisol secretion, while there was a progressive increase in ABR thresholds, which could be overcome with cortisone replacement.

Thermal effects of cold light sources used in otologic surgery.

The objective of this study was to investigate the thermal effects of cold light sources and endoscopes on the inner ear. 25 male guinea pigs were assigned equally to five groups (1: Halogen-1 min, 2: Halogen-5 min, 3: Xenon-1 min, 4: Xenon-5 min, 5: Controls). After both bullae of the guinea pigs were opened, light sources and endoscopes were positioned in the middle ears of the first four groups for specific time periods. DPOAE and ABR tests were conducted on all animals at the beginning of the study, at the end of surgery, and 2 h after surgery. The temperatures of cold light sources were measured by a thermocouple thermometer, and the surface temperatures of the endoscopes were measured by an infrared thermometer. DPOAE and ABR measurements performed right after and 2 h after surgery in group 1, 2, 3, and 5 did not reveal any significant difference. In group 4, DPOAE values were significantly lower and ABR threshold values were significantly higher than those in the other groups, right after and 2 h after surgery. Thermocouple thermometer readings showed that, after the first minute, the Xenon light source generated significantly more temperature rise than the Halogen light source. The surface temperatures of all endoscopes returned to normal approximately 1 min after light sources were turned off. Our study demonstrated that when an endoscope using a Xenon light source was applied to the middle ear for a specific time periods, inner ear functions deteriorated, as reflected by audiologic tests.

Effects of sevoflurane and desflurane on otoacoustic emissions in humans.

Otoacoustic emissions (OAEs) are non-invasive, easy to apply and objective test methods which are widely used to determine the presence of hearing in audiology clinics. Under certain circumstances, the study should be applied under general anesthesia. The aim of this study was to determine the influence of new short-acting inhalation agents, desflurane and sevoflurane, on OAE in humans. These short-acting agents are widely used in general anesthesia. Thirty-one healthy patients who underwent septoplasty and turbinoplasty surgery were included in this study. Unpremedicated patients were anesthetized and monitored by a standard protocol except the inhalation agents. Desflurane and sevoflurane were added to the inhaled gas mixture at ~1MAC, 5-6 % and 1.5-2 %, respectively. Transient evoked otoacoustic emissions and distortion product otoacoustic emissions measured in both ears of each patient preoperatively in the operating room before induction, 5 min after induction, after the completion of surgical procedure while the anesthetic agents are still given and 1 h after surgery in the ward. Between-group and within-group comparisons and correlations with hemodynamic parameters were performed for statistical analysis. The measurements of 26 ears in desflurane group and 28 ears in sevoflurane group were evaluated. There were no differences in initial measurements between groups (p > 0.05). Both groups presented significant decrease in intraoperative measurements and changes in time were statistically significant (p < 0.05). The changes in OAEs were similar to changes in systemic blood pressures. Correlation between OAEs and systemic blood pressures were significant (p < 0.05). In conclusion, sevoflurane and desflurane decreased OAEs around 2-3 dB; OAEs are still measurable under inhalation agents. This provides some findings about the OAE status of patient, but the evaluations should be done with the impact of anesthetic agents in mind.