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A Comprehensive Study of Oxidative Stress in Tinnitus Patients. Indian J Otolaryngol Head Neck Surg 2018; 70:521-526. [PMID: 30464909 DOI: 10.1007/s12070-018-1464-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 07/23/2018] [Indexed: 10/28/2022] Open
Abstract
Oxidative stress is considered to be one of the molecular changes that are the underlying causes of tinnitus. The aim of this study was to investigate the dynamic thiol/disulphide homeostasis as a new oxidative stress parameter in tinnitus patients as well as to investigate the lipid hydroperoxide (LOOH), total antioxidant status (TAS), total oxidant status (TOS) and oxidative stress index (OSI) parameters and compare the results with the results of the healthy control group. A prospective controlled trial was performed on tinnitus patients in Harran University hospital. A total of 70 subjects, including 35 tinnitus patients and 35 healthy individuals participated in this study. Their total thiol, native thiol levels and LOOH, TAS, TOS levels were measured in plasma of all tinnitus patients and healthy volunteers participants. TOS and OSI levels were significantly increased, and TAS levels were significantly lower in the patient groups compared with the control group (p < 0.01). Native thiol levels and Native thiol/total thiol ratios were significantly lower in the tinnitus group compared to the control group (p < 0.01). Disulphide level and disulphide/native thiol and disulphide/total thiol ratios were significantly higher in the patients (p < 0.01). Also, LOOH ratios were significantly higher in the tinnitus group (p < 0.01). The results of this study reveal that in tinnitus cases, the oxidative stress and antioxidant enzyme imbalance were more significant than in healthy control group. The nature of the relationship between oxidative stress and tinnitus should be clarified with larger studies.
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Fitzakerley JL, Trachte GJ. Genetics of guanylyl cyclase pathways in the cochlea and their influence on hearing. Physiol Genomics 2018; 50:780-806. [PMID: 29958079 DOI: 10.1152/physiolgenomics.00056.2018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Although hearing loss is the most common sensory deficit in Western societies, there are no successful pharmacological treatments for this disorder. Recent experiments have demonstrated that manipulation of intracellular cyclic guanosine monophosphate (cGMP) concentrations can have both beneficial and harmful effects on hearing. In this review, we will examine the role of cGMP as a key second messenger involved in many aspects of cochlear function and discuss the known functions of downstream effectors of cGMP in sound processing. The nitric oxide-stimulated soluble guanylyl cyclase system (sGC) and the two natriuretic peptide-stimulated particulate GCs (pGCs) will be more extensively covered because they have been studied most thoroughly. The cochlear GC systems are attractive targets for medical interventions that improve hearing while simultaneously representing an under investigated source of sensorineural hearing loss.
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Affiliation(s)
- Janet L Fitzakerley
- Department of Biomedical Sciences, University of Minnesota Medical School , Duluth, Minnesota
| | - George J Trachte
- Department of Biomedical Sciences, University of Minnesota Medical School , Duluth, Minnesota
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Tamura A, Matsunobu T, Tamura R, Kawauchi S, Sato S, Shiotani A. Photobiomodulation rescues the cochlea from noise-induced hearing loss via upregulating nuclear factor κB expression in rats. Brain Res 2016; 1646:467-474. [PMID: 27342816 DOI: 10.1016/j.brainres.2016.06.031] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Revised: 06/16/2016] [Accepted: 06/20/2016] [Indexed: 12/12/2022]
Abstract
Photobiomodulation (PBM) is a noninvasive treatment that can be neuroprotective, although the underlying mechanisms remain unclear. In the present study, we assessed the mechanism of PBM as a novel treatment for noise-induced hearing loss, focusing on the nuclear factor (NF)-κB signaling pathway. Sprague-Dawley rats were exposed to 1-octave band noise centered at 4kHz for 5h (121dB). After noise exposure, their right ears were irradiated with an 808nm diode laser beam at an output power density of 165mW/cm(2) for 30min a day for 5 consecutive days. Measurement of the auditory brainstem response revealed an accelerated recovery of auditory function in the groups treated with PBM compared with the non-treatment group at 4, 7, and 14 days after noise exposure. Immunofluorescent image analysis for inducible nitric oxide synthase and cleaved caspase-3 showed lesser immunoreactivities in outer hair cells in the PBM group compared with the non-treatment group. However, immunofluorescent image analysis for NF-κB, an upstream protein of inducible nitric oxide synthase, revealed greater activation in the PBM group compared with the naïve and non-treatment groups. Western blot analysis for NF-κB also showed stronger activation in the cochlear tissues in the PBM group compared with the naïve and non-treatment groups (p<0.01, each). These data suggest that PBM activates NF-κB to induce protection against inducible nitric oxide synthase-triggered oxidative stress and caspase-3-mediated apoptosis that occur following noise-induced hearing loss.
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Affiliation(s)
- Atsushi Tamura
- Department of Otolaryngology - Head and Neck Surgery, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-0042, Japan.
| | - Takeshi Matsunobu
- Department of Otolaryngology - Head and Neck Surgery, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-0042, Japan
| | - Risa Tamura
- Department of Physiology, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-0042, Japan
| | - Satoko Kawauchi
- Division of Bioinformation and Therapeutic Systems, National Defense Medical College Research Institute, 3-2 Namiki, Tokorozawa, Saitama 359-0042, Japan
| | - Shunichi Sato
- Division of Bioinformation and Therapeutic Systems, National Defense Medical College Research Institute, 3-2 Namiki, Tokorozawa, Saitama 359-0042, Japan
| | - Akihiro Shiotani
- Department of Otolaryngology - Head and Neck Surgery, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-0042, Japan
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The protective effect of intratympanic dexamethasone on cisplatin-induced ototoxicity in guinea pigs. Otolaryngol Head Neck Surg 2016; 137:747-52. [DOI: 10.1016/j.otohns.2007.05.068] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2006] [Revised: 05/26/2007] [Accepted: 05/31/2007] [Indexed: 11/17/2022]
Abstract
Objective The purpose of this study was to investigate the effectiveness of intratympanic dexamethasone injection as a protection agent against cisplatin-induced ototoxicity. Study Design and Setting The four groups of guinea pigs were injected as follows: 1) cisplatin, 2) intratympanic dexamethasone, 3) cisplatin following intratympanic dexamethasone, and 4) cisplatin after intratympanic saline. Before and 3 days following injections, the ototoxic effect was measured with distortion product otoacoustic emissions (DPOAEs). Results The DPOAEs amplitudes and signal-to-noise ratio (SNR) values at 1 to 6 kHz frequencies for group 1 animals after injections significantly decreased over those before injections ( P < 0.05). In group 2, there were no significant differences in DPOAE amplitude and SNR values between before and after intratympanic dexamethasone injections ( P > 0.05). Considering group 3, there were also no significant differences in DPOAEs amplitudes and SNR values before and after of dexamethasone and cisplatin injections ( P > 0.05). Conclusions Intratympanic dexamethasone injection did not cause any ototoxic effect; in contrast, it might have a significant protective effect after cisplatin injection.
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Koç S, Akyüz S, Somuk BT, Soyalic H, Yılmaz B, Taskin A, Bilinc H, Aksoy N. Paraoxonase Activity and Oxidative Status in Patients with Tinnitus. J Audiol Otol 2016; 20:17-21. [PMID: 27144229 PMCID: PMC4853894 DOI: 10.7874/jao.2016.20.1.17] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Revised: 12/17/2015] [Accepted: 01/21/2016] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND AND OBJECTIVES The aim of this study was to investigate serum paraoxanase-1 (PON) activity, total oxidant status (TOS), total antioxidant status (TAS), and the oxidative stress index (OSI) in tinnitus; and to compare the results with data from healthy subjects. SUBJECTS AND METHODS A total of 114 subjects-54 patients with tinnitus and 60 healthy controls were enrolled in this study. Serum PON activity, TOS, TAS, and OSI levels were measured. RESULTS In the tinnitus group, TAS, and PON were significantly lower than in the control group (p<0.001). However, the TOS, and OSI levels were significantly higher in the tinnitus group than in the control group (p<0.001). CONCLUSIONS According to the data obtained from the present study, patients with tinnitus were exposed to potent oxidative stress. Oxidative stress may be the key contributing factor to the pathogenesis of tinnitus.
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Affiliation(s)
- Sema Koç
- Department of Otorhinolaryngology, Antalya Education and Research Hospital, Antalya, Turkey
| | - Servet Akyüz
- Department of Otorhinolaryngology, Gaziosmanpasa University School of Medicine, Tokat, Turkey
| | - Battal Tahsin Somuk
- Department of Otorhinolaryngology, Gaziosmanpasa University School of Medicine, Tokat, Turkey
| | - Harun Soyalic
- Department of Otorhinolaryngology, Gaziosmanpasa University School of Medicine, Tokat, Turkey
| | - Beyhan Yılmaz
- Department of Otorhinolaryngology, Dicle University School of Medicine, Diyarbakır, Turkey
| | - Abdullah Taskin
- Department of Biochemistry, Harran University School of Medicine, Sanliurfa, Turkey
| | - Hasan Bilinc
- Department of Biochemistry, Harran University School of Medicine, Sanliurfa, Turkey
| | - Nurten Aksoy
- Department of Biochemistry, Harran University School of Medicine, Sanliurfa, Turkey
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Tamura A, Matsunobu T, Mizutari K, Niwa K, Kurioka T, Kawauchi S, Satoh S, Hiroi S, Satoh Y, Nibuya M, Tamura R, Shiotani A. Low-level laser therapy for prevention of noise-induced hearing loss in rats. Neurosci Lett 2015; 595:81-6. [PMID: 25797186 DOI: 10.1016/j.neulet.2015.03.031] [Citation(s) in RCA: 258] [Impact Index Per Article: 28.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Revised: 01/28/2015] [Accepted: 03/17/2015] [Indexed: 11/25/2022]
Abstract
Noninvasive low-level laser therapy (LLLT) is neuroprotective, but the mechanism of this effect is not fully understood. In this study, the use of LLLT as a novel treatment for noise-induced hearing loss (NIHL) is investigated. Sprague-Dawley rats were exposed to intense noise and their right ears were irradiated with an 808nm diode laser at an output power density of 110 or 165mW/cm(2) for a 30min period for 5 consecutive days. Measurement of the auditory brainstem response revealed an accelerated recovery of auditory function in the groups treated with LLLT compared with the non-treatment group at days 2, 4, 7 and 14 after noise exposure. Morphological observations also revealed a significantly higher outer hair cell survival rate in the LLLT groups. Immunohistochemical analyses for inducible nitric oxide synthase (iNOS) and cleaved caspase-3 were used to examine oxidative stress and apoptosis. Strong immunoreactivities were observed in the inner ear tissues of the non-treatment group, whereas these signals were decreased in the LLLT group at 165mW/cm(2) power density. Our findings suggest that LLLT has cytoprotective effects against NIHL via the inhibition of iNOS expression and apoptosis.
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Affiliation(s)
- Atsushi Tamura
- Department of Otolaryngology-Head and Neck Surgery, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-0042, Japan
| | - Takeshi Matsunobu
- Department of Otolaryngology-Head and Neck Surgery, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-0042, Japan.
| | - Kunio Mizutari
- Department of Otolaryngology-Head and Neck Surgery, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-0042, Japan
| | - Katsuki Niwa
- Department of Otolaryngology-Head and Neck Surgery, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-0042, Japan
| | - Takaomi Kurioka
- Department of Otolaryngology-Head and Neck Surgery, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-0042, Japan
| | - Satoko Kawauchi
- Division of Biomedical Information Sciences, National Defense Medical College Research Institute, 3-2 Namiki, Tokorozawa, Saitama 359-0042, Japan
| | - Shunichi Satoh
- Division of Biomedical Information Sciences, National Defense Medical College Research Institute, 3-2 Namiki, Tokorozawa, Saitama 359-0042, Japan
| | - Sadayuki Hiroi
- Department of Pathology and Laboratory Medicine, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-0042, Japan
| | - Yasushi Satoh
- Department of Anesthesiology, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-0042, Japan
| | - Masashi Nibuya
- Department of Psychiatry, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-0042, Japan
| | - Risa Tamura
- Department of Physiology, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-0042, Japan
| | - Akihiro Shiotani
- Department of Otolaryngology-Head and Neck Surgery, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-0042, Japan
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Heinrich UR, Helling K. Nitric oxide--a versatile key player in cochlear function and hearing disorders. Nitric Oxide 2012; 27:106-16. [PMID: 22659013 DOI: 10.1016/j.niox.2012.05.005] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2012] [Revised: 05/10/2012] [Accepted: 05/24/2012] [Indexed: 12/13/2022]
Abstract
Nitric oxide (NO) is a signaling molecule which can generally be formed by three nitric oxide synthases (NOS). Two of them, the endothelial nitric oxide synthase (eNOS) and the neural nitric oxide synthase (nNOS), are calcium/calmodulin-dependent and constitutively expressed in many cell types. Both isoforms are found in the vertebrate cochlea. The inducible nitric oxide synthase (iNOS) is independent of calcium and normally not detectable in the un-stimulated cochlea. In the inner ear, as in other tissues, NO was identified as a multitask molecule involved in various processes such as neurotransmission and neuromodulation. In addition, increasing evidence demonstrates that the NO-dependent processes of cell protection or, alternatively, cell destruction seem to depend, among other things, on changes in the local cochlear NO-concentration. These alterations can occur at the cellular level or within a distinct cell population both leading to an NO-imbalance within the hearing organ. This dysfunction can result in hearing loss or even in deafness. In cases of cochlear malfunction, regulatory systems such as the gap junction system, the blood vessels or the synaptic region might be affected temporarily or permanently by an altered NO-level. This review discusses potential cellular mechanisms how NO might contribute to different forms of hearing disorders. Approaches of NO-reduction are evaluated and the transfer of results obtained from experimental animal models to human medication is discussed.
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Affiliation(s)
- Ulf-Rüdiger Heinrich
- Department of Otorhinolaryngology, Head and Neck Surgery, University Medical Center of The Johannes Gutenberg-University Mainz, Germany.
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Lendvai B, Halmos GB, Polony G, Kapocsi J, Horváth T, Aller M, Sylvester Vizi E, Zelles T. Chemical neuroprotection in the cochlea: The modulation of dopamine release from lateral olivocochlear efferents. Neurochem Int 2011; 59:150-8. [DOI: 10.1016/j.neuint.2011.05.015] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2010] [Revised: 05/12/2011] [Accepted: 05/17/2011] [Indexed: 01/16/2023]
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Role of oxidative stress in hearing impairment in patients with type two diabetes mellitus. The Journal of Laryngology & Otology 2009; 123:957-63. [PMID: 19203398 DOI: 10.1017/s0022215109004502] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
OBJECTIVE Although many clinical investigations have found a relationship between hearing loss and diabetes mellitus, the pathophysiology of this effect remains controversial. To date, the mechanisms of hearing loss in diabetic patients have been explained in terms of microangiopathy, neuropathy and encephalopathy. However, many reports indicate that some diabetic complications are associated with oxidative stress related to the diabetes itself. In the present study, we hypothesised that oxidative stress may be a cause of hearing loss in diabetic patients. METHODS The study group comprised non-insulin dependent diabetic patients with no signs of microangiopathy or peripheral neuropathy. The control group comprised sex-, age- and body weight matched, non-diabetic subjects. Auditory function was evaluated using pure tone audiometry and tympanometry. Subjects with normal hearing and sensorineural hearing loss were included in the study, whereas subjects with conductive hearing loss were excluded. Both the study group (n = 63) and the control group (n = 37) were divided into subgroups based on the presence and absence of hearing loss. Oxidative stress was evaluated by measuring serum indicators of protein oxidation and lipid peroxidation, serum levels of nitric oxide and various non-enzymatic antioxidants, and the activity of various enzymatic antioxidants. RESULTS The non-insulin dependent diabetic patients had significantly higher serum levels of protein oxidation products, nitric oxide, enzymatic antioxidant activity (i.e. glutathione peroxidase and superoxide dismutase), compared with the control group (p < 0.05). When we compared the groups in relation to the presence of hearing loss, the nitric oxide level was significantly increased in the diabetic group with good hearing, compared with diabetic patients with hearing loss (p = 0.014). In the diabetic group, a clear, negative correlation was observed between serum levels of nitric oxide and vitamins C and E, and hearing impairment (r = -0.395, r = -0.318, r = -0.500, respectively). There was also a positive correlation between serum vitamin C concentrations and hearing levels in the control group (r = 0.417). CONCLUSION These results suggest that oxidative stress may play an important role in hearing impairment in diabetic patients. In this process, increased protein oxidation appears to be more important than lipid peroxidation. Nitric oxide may have a protective effect on hearing, as may some nonenzymatic antioxidants such as vitamin C and E.
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Ikino CMY, Bittar RSM, Sato KM, Capella NM. Effects of a Nitric Oxide Synthase Type II Inhibitor on Compound Action Potential Thresholds in Experimental Endolymphatic Hydrops. Otol Neurotol 2007; 28:111-5. [PMID: 17031325 DOI: 10.1097/01.mao.0000231591.64972.80] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
HYPOTHESIS Nitric oxide (NO) is likely to be synthesized by nitric oxide synthase Type II (NOS II) action and may partake in the origin of changes of compound action potential (CAP) threshold observed in guinea pigs with induced endolymphatic hydrops. This study aimed to assess the action of a NOS II inhibitor on CAP thresholds in these experimental samples. BACKGROUND In guinea pigs with experimental endolymphatic hydrops, there are lesions on the cochlea and progressive increase of CAP threshold. NOS II was found in the cochlea of this animal model, and it was inferred that NO can contribute by such alterations. METHODS The animals were divided into two groups, in which eight received an intake of a NOS II inhibitor, aminoguanidine, and another eight served as a control group. During 16 weeks, CAP thresholds at 1,000, 2,000, 4,000 and 6,000 on electrocochleography were compared between the groups. RESULTS The group that had an intake of aminoguanidine showed a lower increase on CAP thresholds at 2,000 (p < 0.05) and 6,000 Hz (p < 0.05) at the 12th postoperative week, and at 1,000 (p < 0.05), 2,000 (p < 0.001), 4,000 (p < 0.001), > and 6,000 Hz (p < 0.001) at the 16th week. CONCLUSION We conclude that NOS II inhibitor reduced the elevation of CAP thresholds in experimentally induced endolymphatic hydrops.
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Ikino CMY, Bittar RSM, Sato KM, Capella NM. Experimental endolymphatic hydrops under action of a type II nitric oxide synthase inhibitor: otoacoustic emissions evaluation and electrocochleography. Braz J Otorhinolaryngol 2006; 72:151-7. [PMID: 16951846 PMCID: PMC9445774 DOI: 10.1016/s1808-8694(15)30049-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2006] [Accepted: 03/09/2006] [Indexed: 12/03/2022] Open
Abstract
In experimental endolymphatic hydrops distortion-products otoacoustic emission (dpoae) amplitudes decrease and there is elevation on electrocochleographic thresholds. Some authors found type ii nitric oxide synthase (nos ii) expression in hydropic cochleas and they suggest nitric oxide (no) may be involved in endolymphatic hydrops pathogenesis. The aim of this study was to evaluate the action of a nos ii inhibitor on dpoae and electrocochleography in experimental endolymphatic hydrops. Material and methods: endolymphatic hydrops was induced in 16 guinea pigs by obliterating the endolymphatic duct and sac in the right ear. They were divided in two groups: eigth guinea pigs under the action of aminoguanidine, a nos ii inhibitor and eigth control guinea pigs. We compared dpoae amplitudes at geometric means of frequencies 1062, 2187, 4375 and 7000 hz, compound action potential threshold at 1000, 2000, 4000 and 6000 hz and summating potential to action potential (sp/ap) ratio between the groups during the postoperative observation period of 16 weeks. Results: there were no significant changes in the dpoae amplitudes and in the sp/ap ratio. The group that received aminoguanidine had a lower degree of threshold increase at 2000 (p<0.05) And 6000 hz (p<0.05) In 12th postoperative week and at 1000 (p<0.05), 2000 (P<0.001), 4000 (P<0.001) And 6000 hz (p<0.001) At 16th postoperative week. Conclusions: nos ii inhibitor decreased the electrocochleography threshold elevation on experimental endolymphatic hydrops.
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Dagilas A, Kimiskidis V, Aggelopoulou M, Kapaki E, Fitili C, Libitaki G, Papagiannopoulos S, Kazis D, Kazis A, Aidonis A. Changes In Blood Neurotransmitter And Steroid Levels During Evoked Vertigo. Otol Neurotol 2005; 26:476-80; discussion 480. [PMID: 15891652 DOI: 10.1097/01.mao.0000169785.15083.28] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
HYPOTHESIS AND BACKGROUND Experimental evidence suggests that steroids as well as various neurotransmitters are critically involved in the functioning of the vestibular system in health and disease. Yet there are no pertinent human data. We hypothesized that changes in the serum levels of cortisol and plasma levels of excitatory and inhibitory neurotransmitters may occur during evoked vertigo. SUBJECTS AND METHODS Ten healthy volunteers (median age 37, range 21-57) entered the study. Subjects were investigated at rest and at the time of maximal nystagmic reaction during caloric irrigation. The determination of glutamate, aspartate, and gamma-aminobutyric acid (GABA) was performed by reverse phase high-performance liquid chromatography, whereas cortisol measurements were performed with an immunoenzymatic assay with fluorescence polarization. RESULTS During evoked vertigo, cortisol levels increased from a baseline value of 11.86 (+/-1.272) microg/dl to 14.375 (+/-2.183) microg/dl (p < 0.01), whereas all neurotransmitter levels decreased significantly. Glutamate levels, for instance, fell from a resting value of 25.99 (+/-6.30) ng/ml to 17.40 (+/-5.50) ng/ml (p < 0.001), and aspartate and GABA decreased as well. CONCLUSION Evoked vertigo is consistently associated with an increase in steroid serum levels and accompanying decreases in the plasma levels of glutamate, aspartate, and GABA. The possible underlying mechanisms and the functional significance of these findings are discussed.
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Affiliation(s)
- A Dagilas
- Unit of Neuro-Otology, ENT Department, G. Papanikolaou Hospital, Thessaloniki, Greece
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Banerjee A, Parnes LS. The biology of intratympanic drug administration and pharmacodynamics of round window drug absorption. Otolaryngol Clin North Am 2005; 37:1035-51. [PMID: 15474109 DOI: 10.1016/j.otc.2004.04.003] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The application of therapeutic agents to the round window holds great promise in the treatment of inner ear disease. The primary benefit of this route of administration is the ability to achieve high inner ear concentrations of drugs without systemic side effects. Recent research has elucidated the anatomy and physiology of the round window and provided important information on the inner ear pharmacokinetics and the pharmacodynamics of drugs administered intratympanically. Although amino-glycosides and steroids have been most thoroughly studied, many other classes of pharmaceuticals, including otoprotective agents, other antibiotics,and topical anesthetics, have therapeutic potential in the inner ear and will probably be the subject of future studies. The authors believe that direct delivery approaches other than through the round window, perhaps with slow or sustained release formulations, may hold the key to the future treatment of inner ear disorders.
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Affiliation(s)
- Avik Banerjee
- Department of Otolaryngology, University of Western Ontario, London Health Sciences Centre, 339 Windermere Road, London, Ontario, N6A 5A5, Canada
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Abstract
Cisplatin is known to cause high-frequency neurosensory hearing loss. While reactive oxygen species have been shown to play a role, reactive nitrogen species have been implicated, but not proven to be involved, in cisplatin ototoxicity. The purpose of the present study was to investigate the role of nitric oxide (*NO) in cisplatin ototoxicity by administering aminoguanidine (AG), a relatively specific inhibitor of inducible nitric oxide synthase (iNOS), in conjunction with cisplatin. Rats were injected with cisplatin, AG, or both. Auditory brainstem evoked responses (ABR) were measured before and 3 days after cisplatin administration. The cochlear tissue was then assayed for *NO and malondialdehyde. Cisplatin alone caused significant ABR threshold shifts at all stimuli tested, whereas AG alone caused no shifts. There was a significant reduction in threshold shift for clicks and 16 kHz tone bursts (but not 32 kHz) when AG was given with cisplatin. The malondialdehyde concentration (but not the *NO concentration) in the AG/cisplatin group was significantly lower than that of the cisplatin group. This suggests that AG reduces cisplatin ototoxicity by directly scavenging hydroxyl radicals. The iNOS pathway may play a role in the generation of free radicals and hearing loss resulting from cisplatin administration, but this conclusion was not supported by our data.
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Affiliation(s)
- Thomas C Kelly
- Southern Illinois University School of Medicine, Department of Surgery, P.O. Box 19638, Springfield, IL 62794-9653, USA
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Takumida M, Anniko M, Ohtani M. Radical scavengers for Ménière's disease after failure of conventional therapy: a pilot study. Acta Otolaryngol 2003; 123:697-703. [PMID: 12953767 DOI: 10.1080/00016480310000728a] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
OBJECTIVE To perform a trial to assess the efficacy of radical scavengers, i.e. rebamipide, vitamin C and glutathione, for the treatment of Ménière's disease (MD). MATERIAL AND METHODS Rebamipide (300 mg/day), vitamin C (600 mg/day) and/or glutathione (300 mg/day) were given orally for at least 8 weeks to 25 patients with poorly controlled MD. RESULTS Of 22 patients, 21 showed marked improvement of vertigo; 12/27 ears showed improvement of hearing disorders; 17/27 ears showed improvement of tinnitus; and 18/25 patients showed improvement of disability. CONCLUSION This study suggests that treatment using radical scavengers has the potential to become an effective new therapy for MD.
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Affiliation(s)
- Masaya Takumida
- Department of Otolaryngology, Hiroshima University School of Medicine, Hiroshima, Japan.
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Takumida M, Anniko M. Simultaneous detection of both nitric oxide and reactive oxygen species in guinea pig vestibular sensory cells. ORL J Otorhinolaryngol Relat Spec 2002; 64:143-7. [PMID: 12021507 DOI: 10.1159/000057794] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Gentamicin-induced production of reactive oxygen species (ROS) and of nitric oxide (NO) in the vestibular end organs of the guinea pig was investigated by applying two new fluorescence indicators, 4,5-diaminofluorescein diacetate for direct detection of NO and dihydrotetramethylrosamine for ROS. The vestibular sensory cells produced both NO and ROS after exposure to gentamicin. A nonspecific inhibitor of NO synthase, L-NAME, inhibited the production of NO but did not appear to affect the production of ROS following exposure to gentamicin. In contrast, a radical scavenger, D-methionine, or the neurotrophin BDNF suppressed the production of ROS, in turn stimulating NO production. These findings could indicate that both NO and ROS play an important role in aminoglycoside ototoxicity.
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Affiliation(s)
- Masaya Takumida
- Department of Otolaryngology, Hiroshima University Faculty of Medicine, Hiroshima, Japan.
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Shi X, Ren T, Nuttall AL. The electrochemical and fluorescence detection of nitric oxide in the cochlea and its increase following loud sound. Hear Res 2002; 164:49-58. [PMID: 11950524 DOI: 10.1016/s0378-5955(01)00409-9] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A nitric oxide (NO)-selective sensor (tip diameter 30 microm) was inserted into the perilymph of the basal turn of the guinea pig cochlea. The basal level and stimulation-induced changes of NO were measured. The mean (+/-S.E.M.) basal level of NO was 273+/-42.9 nM. Following perilymphatic perfusion of the artificial perilymph containing NO synthase (NOS) substrate L-arginine (100 microM) combined with cofactor (6R)-5,6,7,8-tetrahydrobiopterin dihydrochloride (100 microM), a rapid and significant increase of NO to a mean concentration of 392+/-32.3 nM (P < 0.01, n = 10) was recorded. In contrast, a significant decrease of mean NO concentration to 180+/-32.7 nM (P < 0.01, n = 10) was observed following the perfusion of the NOS-inhibiting agent N(G)-nitro-L-arginine methyl ester (100 microM). No change in the NO concentration was found following the perfusion of either artificial perilymph or N(G)-monomethyl-D-arginine (100 microM) solution employed as controls. Broadband noise exposure (3 h/day at 120 dBA SPL) for three consecutive days produced an increase in NO concentration to 618+/-60.7 nM (P < 0.05, n = 10) in the perilymph. In addition, by using specific dyes for NO, 4,5-diaminofluoresceine diacetate and for the reactive oxygen species (ROS), dihydrorhodamine 1,2,3, the distribution of NO in the whole mounts of the organ of Corti and the production of ROS in vivo in the organ of Corti were investigated in both control (n = 5) and noise-exposed (n = 5) animals. The more intense NO and ROS fluorescence was observed in both the inner and outer hair cells in the noise-exposed groups. It is proposed that both the basal level and the increase in NO concentration following the addition of substrate (L-arginine) are produced by the constitutive NOS while the elevated NO and ROS following noise exposure indicate that NO may be involved in noise-induced hearing loss.
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Affiliation(s)
- Xiaorui Shi
- Department of Otolaryngology, the General Hospital of the CPAPA, Beijing 100039, PR China
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Takumida M, Anniko M. Brain-derived neurotrophic factor and nitric oxide synthase inhibitor protect the vestibular organ against gentamicin ototoxicity. Acta Otolaryngol 2002; 122:10-5. [PMID: 11876587 DOI: 10.1080/00016480252775661] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
In order to find a way to develop a new treatment for inner ear disorders, the effects of a nitric oxide synthase (NOS) inhibitor [N-nitro-L-arginine methylester (L-NAME)] and a neurotrophin [brain-derived neurotrophic factor (BDNF)] were investigated. The effect of L-NAME and BDNF on gentamicin-induced vestibular hair cell damage was investigated by using the in vitro LIVE/DEAD system. Both L-NAME and BDNF individually reduced the vestibular hair cell damage caused by gentamicin but the combination of L-NAME and BDNF was more successful in preventing damage. It is therefore suggested that treatment with a combination of an NOS inhibitor and a neurotrophin will help us to treat inner ear disorders.
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Affiliation(s)
- Masaya Takumida
- Department of Otolaryngology, Hiroshima University Faculty of Medicine, Japan.
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