Preventive and Therapeutic Effects of Low Level Laser Irradiation on Gentamicin-Induced Vestibulotoxicity in Rat Utricles / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: The purpose of this study was to investigate the effects of low level laser for the prevention and treatment of aminoglycoside-induced vestibular ototoxicity. MATERIALS AND METHOD: An organotypic culture of 2 to 4 days old rat utricular maculae was established. Rats were divided into 6 groups according to the treadtment of the utricles: G (gentamicintreated), L (laser-irradiated), LG (laser-irradiated and gentamicin-treated), GL (gentamicin-treated and laser-irradiated), LGL (gentamicin-treated during laser-irradiated) and C (control). After organotypic culture, the utricles of 6 groups were examined by confocal laser scanning electron microscope and scanning electron microscope. The results of each group were compared with each other by statistical methods. RESULTS: The number of vestibular hair cells of the group G was smaller compared to that of the group C. The group L had no difference compared with the group C. The groups LG and GL showed more vestibular hair cells compared with the group G. The group LG showed more vestibular hair cells than the group GL. The group LGL showed most vestibular hair cells compared to that of the groups G, LG, and GL. CONCLUSION: The most effective treatment of aminoglycosideinduced vestibular otoxicity is the irradiation of low level laser before and after the insult of the aminoglycoside. Further clinical studies using low level laser were needed to prevent aminoglycoside-induced ototoxicity and to promote the regeneration of vestibular hair cells.

A Case of Complicated BPPV(Benign Paroxismal Positional Vertigo)

Canalith repositioning maneuver is effective to treat benign paroxysmal positional vertigo(BPPV). This case showed complicated form of the BPPV such as changes of canalolithiasis to cupulolithiasis, involvement of one canal to two canals and from unilateral to bilateral involvement during the reposition maneuver. This patient was diagnosed as left lateral canalolithiasis at first. After left barbecue maneuver, the type was changed to the right posterior cupulolithiasis. Semont maneuver was performed and then the type of BPPV was changed to combined type with right posterior canalolithiasis and left lateral canalolithiasis. We performed left barbecue maneuver and right Epley maneuver. Then the type of BPPV was changed to left lateral cupulolithiasis. After Brandt-Daroff maneuver and left barbecue maneuver, nystagmus and dizziness disappeared finally.

Recurrent Episodic Vertigo Controlled by Phenytoin Sodium

BACKGROUND:Many patients with symptom of recurrent episodic vertigo can neither be diagnosed nor treated. The purpose of this study is to review clinical features of a group of patients with recurrent episodic vertigo that is not defined to specific diagnosis of vertigo and to test the effectiveness of phenytoin sodium in the patients. METHOD & MATERIAL:11 of 32 patients with recurrent vertigo not defined to specific diagnostic category of vertigo who visited dizziness center of a tertiary care university hospital from November 1995 to April 2004 were studied. The patient's charts were reviewed retrospectively. A thorough otolaryngologic and neurotologic evaluation was performed in every case to determine the specific cause of dizziness. Vestibular function test, hearing test, magnetic resonance imaging of brain, electroencephalogram, and 24 hour Holter EKG monitoring were performed in all cases. Consultations to psychiatrist and neurologist were obtained. All patients were treated with phenytoin sodium. RESULT:The results of the vestibular function test, audiogram, MRI of brain, electroencephalogram, 24-hr holter monitoring were normal. Any definitive diagnosis could not be reached to this group. Vertigo was controlled by phenytoin sodium in all 11 cases. CONCLUSION:We report a group of patients with recurrent episodic vertigo that is not defined to any specific diagnosis of vertigo. The vertigo symptom was controlled successfully by phenytoin sodium. This patients were diagnosed as benign episodic vertigo as a separate disease entity.

Audiologic Follow-up Evaluation of Patients with Hyperbilirubinemic Sensorineural Hearing Loss / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: In neonates with hyperbilirubinemic sensorineural hearing loss, the lesion site is supposed to be confined to the retrocochlea. The purpose of this study is to investigate the changes of hearing level and the progression of the lesion site involving cochlear area after a lapse of time in the patients with hyperbilirubinemic sensorineural hearing loss. MATERIALS AND METHOD: ABR, TEOAE and IA tests were performed on 11 neonates with severe hyperbilirubinemia with exchange transfusion in the period of neonates. After more than 4 years, follow-up ABR, TEOAE, and IA tests were carried out in the same 11 children. RESULTS: In the initial ABR test, 4 neonates showed abnormal or no response and the other 7 neonates demonstrated normal response. All 11 neonates passed TEOAE and showed A type in IA In the follow-up tests after more than 4 years, 7 children who had shown normal ABR, TEOAE and IA test results as neonates showed normal ABR, TEOAE, and IA. In 4 children who had abnormal ABR results, showed decreased ABR thresholds. In TEOAE, 3 children showed bilateral failures and 1 child showed unilateral failure. CONCLUSIONS: The results of this study suggests that the sites of lesion in hearing loss caused by hyperbilirubinemia were at the retrocochlear location as neonates. But the lesions may affect the cochlear lesions after a lapse of time. And some residual hearing may be preserved.

The Ototoxicity of Cisplatin is Mediated by NO: A Study using L-NAME and MK-801 in Guinea pigs / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Nitric oxide has been suggested to play an important role in the pathogenesis of cisplatin ototoxicity. L-NAME (NG-Nitroarginine Methyl Ester) is an inhibitor of nitric oxide synthase. MK-801 (Dizocilpine Maleate) is a NMDA receptor antagonist. To evaluate a role of nitric oxide in cisplatin ototoxicity, we investigated whether L-NAME and MK-801 can block the cisplatin ototoxicity in guinea pigs. MATERIALS AND METHOD: In the Group 1, normal saline was injected intraperitoneally as a control group. Group 2, 3, 4, and 5 were injected intraperitoneally as described in the following: Group 2, cisplatin only; Group 3, L-NAME+isplatin; Group 4, MK-801+cisplatin; Group 5, L-NAME+K-801+cisplatin. Using an auditory brainstem response, hearing threshold was tested before cisplatin administration and 5 days after cisplatin injection in each group. The morphological changes of the cochlea were observed by scanning electron microscopy. RESULTS: In the Group 2, a significant hearing loss was observed comparing to Group 1. In contrast , Group 3, 4, and 5 did not demonstrate any significant hearing loss compared to Group 1. In the scanning electron microscopy, the Group 2 showed distorsion and loss of stereocilia of the hair cells. However, the Group 1, 3, 4, and 5 demonstrated well preserved cochlear hair cell morphology. CONCLUSION: Hearing loss induced by ototoxicity of cisplatin was prevented by L-NAME and MK-801. This study suggests that NO may mediate cisplatin ototoxicity.