The Protective Effect of Epigallocatechin-3-Gallate Against Gentamicin Vestibular Ototoxicity in Type I Vestibular Hair Cell of Guinea Pig / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Gentamicin (GM) is well known for its vestibulotoxicity. There have been many reports about vestibulotoxicity, however, its mechanism is still unclear. So far, it is known that GM affects the voltage-dependent K+ current and nitric oxide (NO) production. Epigallocatechin-3-gallate (EGCG) is the major component of green tea and is known to have anti-oxidative and anti-toxic effect. This study was undertaken to investigate the protective effect of EGCG against gentamicin on vestibular hair cell (VHC). MATERIALS AND METHOD: White guinea pigs (200-250 g) were rapidly decapitated and the temporal bones were immediately removed. Under a dissecting microscope, the crista ampullaris was obtained. The dissociated VHCs were transferred into a recording chamber mounted onto an inverted microscope. Whole-cell membrane currents and potentials were recorded using standard patch-clamp techniques. In addition, measurements of NO production were obtained using the NO-sensitive dye, 4,5-diamino-fluorescein diacetate (DAF-2DA). RESULTS: Type I VHCs Voltage-dependent K+ current was activated from low depolarizing stimulation. As the stimulation increased, higher current was detected. Voltage-dependent K+ current in type I VHCs was decreased when GM (200 microM) was administrated and GM effects of K+ current inhibition was significantly blocked by EGCG. Extracellular GM-induced an increase in DAF-2DA fluorescence, which thus indicates NO production in VHCs. Also, the GMinduced NO production was inhibited by EGCG. CONCLUSION: GM inhibits voltage-dependent K+ current by releasing NO in isolated type I VHCs. EGCG blocks this inhibitory effects, suggesting a protective role on GM vestibulotoxicity.

Effects of Aminoglycoside Antibiotics on Acetylcholine-induced Potassium Currents in Guinea-pig Outer Hair Cell / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Aminoglycoside antibiotics are widely used for the treatment of infection caused by Gram-negative bacilli, but prolonged exposure to it can cause permanent hearing loss since are reported to interrupt the function of medial olivocochlear bundle. This study was designed to explore the effects of several aminoglycoside antibiotics on acetylcholine, the neurotransmitter of medial olivocochlear bundle, and how it affects potassium currents of the guinea pig outer hair cells. MATERIALS AND METHOD: Using extracted outer hair cells from Guinea pigs, potassium currents induced by acetylcholine were recorded using the whole-cell patch clamp technique. The effects of different aminoglycoside antibiotics on the potassium current were also studied. RESULTS: Acetylcholine increased the potassium currents of outer hair cells. All of aminoglycoside antibiotics tested such as neomycin, streptomycin, gentamicin, and amikacin decreased the acetylcholine-induced potassium current. CONCLUSION: These experimental results suggest that aminoglycoside antibiotics have effects on the membrane potential of outer hair cells regulated by acetylcholine, which is thought to be one of the mechanisms of aminoglycoside ototoxicity.

A Case of Ectopic Cervical Thymus Presenting as a Submandibular Mass / 대한이비인후과학회지

Ectopic cervical thymus is an extremely uncommon etiology of neck mass in infants. We report a case of ectopic thymus in five months old male baby, presenting as a submandibular mass. Ultrasonography and CT scan revealed a 5.2 x 1.6 x 1.5 cm-sized solid mass in the left suprahyoid neck between parotid and submandibular gland, which was regarded as malignant lesion though it was soft, non-tender on examination. For differential diagnosis of malignant lymphoma and soft tissue sarcoma, an incisional biopsy was performed to confirm ectopic cervical thymus. He is under our observation without having gone through surgical excision because the thymus will involute spontaneously and he has no symptoms.

The Effect of Postural Restrictions in the Treatment of Benign Paroxysmal Positional Vertigo / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: The treatment of Benign Paroxysmal Positional Vertigo (BPPV) consist of repositioning maneuver in order to remove otolithic debris, and subsequent postural restrictions to prevent debris from reentering into the canal. But, it is doubtful how much postural restrictions could have an effect on the final outcomes of BPPV. The purpose of this study is to find out the effect of postural restrictions when imposed on as one of the treatment methods of BPPV, out-broken due to otolithic debris in the posterior semicircular canal, and to find out the necessity of postural restrictions. SUBJECTS AND METHOD: Seventy cases diagnosed as BPPV of the posterior semicircular canal were studied. All the patients were treated by modified Epley Maneuver. They were divided into two groups. The first group (group A, 35 patients) was instructed to sleep in a semi-sitting position and not to move their heads forward or backward, whereas the second group (group B, 35 patients) was not taught to do any specific thing. The gathered information from all the patients was analyzed by age of onset, gender, duration of the disease, and cure rates or recurrence rates. RESULTS: In group A, the average age was 54.5 years and mean duration of symptoms was 116.5 days. On the other hands, in the group B, the average age and the mean duration was 54.8 years and 86.7 days, respectively. The cure rates of the group A and B were 91.4% and 94.3%, respectively. The recurrence rates were 12.5% and 9.1% for group A and group B patients, respectively. No statistically significant difference was found between two groups regarding patient age, duration of symptoms, and cure rates or recurrence rates. CONCLUSION: From the analysis of this study, it can be said that postural restrictions imposed after the repositioning maneuver do not have a significant effect on the final outcomes of BPPV, so they are not recommendable.

A Case of External Jugular Vein Thrombophlebitis with Sepsis / 대한이비인후과학회지

Septic thrombophlebitis results from extensive infection of the lateral pharyngeal space to the jugular vein and generally occurs in healthy adolescents and young adults. This disease can disseminate to multiple distant sites such as joint, liver, kidney, eye, bone, and especially lung, and can lead patients into fatal condition. Contrast enhanced computed tomography and ultrasonography are good diagnostic methods for external jugular vein thrombophlebitis (EJVT). Treatment of EJVT includes intravenous antibiotics and surgical drainage of abscess, ligation or excision of the jugular vein, in addition to fibrinolytic agents and anticoagulants. With a review of literature, authors report a case of external jugular vein thrombophlebitis with sepsis which has successfully been managed by ligation and excision of the vein.

A Case of Thornwaldt's Cyst Removed with Nasal Endoscopy / 대한이비인후과학회지

Thornwaldt's cyst is a rare benign developmental lesion induced by persistent notocord remnants within the midline nasopharynx. Although most patients with the cyst are symptom-free, inflammation or an abscess can develop. Treatment involves excision or wide marsupialization of the cyst. In previous reports, the cysts have been removed transorally by adenoid currette, scissors, and so on. But recently by introduction of nasal endoscopy and its extended application, transnasal approach using nasal endoscopy becomes useful surgical approach to nasopharynx. We report a case of Thornwaldt's cyst which was successfully removed with nasal endoscopy in a 30-year-old man.

Prognostic Significance of the Microvessel Density in Nasopharyngeal Carcinoma / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: The nasopharyngeal cancer (NPC) of nasopharyngeal neoplasms is a rare disease with a relatively poor prognosis, because they tend to be diagnosed in the far advanced stage. Therefore, radiotherapy had been the treatment of choice. Angiogenesis is a crucial step in the tumor growth and progression. The authors attempted to investigate the prognostic value of the microvessel density in NPC. SUBJECTS AND METHOD: We analyzed tumor tissues from 57 cases of paraffin block specimens which had been diagnosed with NPC and treated at Chonnam National University Hospital. The anti-human von Willebrand factor antibody was used to determine the microvessel density (MVD). RESULTS: The MVD was 48.5 in the early stage (stage I and II) and 51.2 in the advanced stage (stage III and IV), which were not statistically significant (p=0.057). The MVD was 55.3 in type I, 54.4 in type II, and 41.8 in type III, and there were no statistical significance between these values (p=0.36). The MVD was not statistically significant between T and N stages (p=0.26, 0.42). There was no significance between the MVD and the survival rates (p>0.05). CONCLUSION: The results suggest that the MVD was not a prognostic significance in NPC.