BACKGROUND: We tried to see if the change in subcellular distribution of estrogen receptor alpha(ER-alpha) was occurring in the senescent or differentiated cells. And if any, we also tried to observe the similarities or differences of distribution changes in ER-alpha in these two groups. METHODS: By treatment with 3'-Azido-3'-deoxythymidine(AZT, Sigma-Aldrich, USA, 1micrometer) on PC12 pheochromocytoma cells line(ATCC CRL-1721). Immunohistochemistries with anti-ER-alpha antibody were also performed on the cells without treatment of AZT, with treatment of 74 days and 140 days. The same staining was also done on the arti-ficially differentiated cells induced by nerve growth factor(50ng/ml) for 5 days. The distribution of ER-alpha in these two cell groups were compared by confocal laser microscope. RESULTS: Senescent PC12 cells treated with AZT showed the changes in morphologies or cell sizes, comparing with normal counterparts. Subcellular localization of ER-alpha in cytoplasmic compartment increased in the cells treated with AZT during much longer duration. Same change in subcelluar distribution was also identified in the cells treated with NGF. In fully differentiated cells, we could find the presence of ER-alpha mainly in the cytoplasmic compartment. However, as to the organelles expressing ER-alpha, senescent and differentiated cells showed differences; mainly expressed in mitochondria in differentiated cells; but expressed diffused in cytoplasm in senescent cells. CONCLUSION: We could see the similarities in subcellular distribution of ER-alpha in the artificially senescent and differentiated neuronal cells. Increase in cytoplasmic expression of ER-alpha in cytoplasm was found in much senescent or differentiated cells. Considering that cell proliferation decrease both in senescence and differentiation, increase in ER-alpha in cytoplasmic compartment might be caused by decrease in cell proliferation of these two changes. This means that estrogen might play a role in inhibiting cell proliferation via its increased receptors within cytoplasmic compartment. In addition, we also found the differences in organelles expressing ER-alpha in both cases, suggesting that minor differences in mechanism for action of estrogen in both cases of senescent and differentiated cells. Estrogen might play a major role through mitochondria in cell differentiation; but not in cell senescence.
Aging ; Animals ; Cell Proliferation ; Cell Size ; Cells, Cultured ; Cytoplasm ; Estrogens ; Mitochondria ; Nerve Growth Factor ; Neurons ; Organelles ; PC12 Cells ; Pheochromocytoma ; Zidovudine

BACKGROUND AND OBJECTIVES: Recent works have demonstrated the existence of ocular vestibular evoked myogenic potentials (OVEMPs), which reflects otolith-ocular reflex. The purpose of this study was to identify an appropriate gaze position to detect OVEMPs produced by air-conducted sound stimulation in healthy subjects. SUBJECTS AND METHOD: Twenty four healthy subjects (35 ears) were included in this study. Surface electromyographic activity was recorded from active electrodes placed inferior to each eye. Stimulation with 500 Hz short tone bursts was used to activate the vestibular end-organs. RESULTS: Sound stimulation evoked negative-positive biphasic responses on both ipsilateral and contralateral eyes, while responses were contralateral eye-dominant. Contralateral eye responses had higher response incidence and larger amplitudes. Altering the direction of gaze generally changed the incidence and size of the inter-peak amplitudes. The higher incidence and larger amplitudes were recorded when the eyes are directed to the superior and ipsilateral side to the sound stimulation. In that gaze position, the amplitude was 5.3 micronV, the first negative peak latency was 10.5 ms and the following positive peak latency was 15.4 ms on the average. CONCLUSION: OVEMPs can be evoked using an air-conducted 500 Hz tone burst and are best recorded contralaterally with a upward gaze towards the source of sound stimulation. Further changes of the test parameters are needed for higher and consistent responses.
Electrodes ; Evoked Potentials ; Eye ; Incidence ; Reflex ; Reflex, Vestibulo-Ocular ; Saccule and Utricle ; Vestibular Evoked Myogenic Potentials

BACKGROUND AND OBJECTIVES: It is necessary to establish the most efficient diagnostic and therapeutic method for benign paroxysmal positional vertigo (BPPV), which is appropriate for Korean healthcare system. We aimed to evaluate current state of Korean clinician's diagnostic and therapeutic approaches for BPPV. MATERIALS AND METHODS: A 16-item survey was emailed to the members of dizziness department of Otology Research Interest Group in the Korean Otologic Society (n=68). 43 were returned and analyzed. RESULTS: All respondents (100%) used Dix-Hallpike test as a diagnostic tool for vertical canal-BPPV. Supine roll test was used for diagnosing lateral canal BPPV in nearly all the respondents (97.7%). Epley maneuver was chosen as otolith repositioning maneuver (ORM) for posterior canal BPPV in all respondents and barbecue rotation (BBQ) was used for treating lateral canal BPPV with geotropic nystagmus in 95.3% of respondents. Extreme variation was noted for therapeutic approach of lateral canal BPPV with ageotropic nystagmus BBQ, with 4 kinds of ORM and adjunctive measures to liberate otolith from cupula, while BBQ was again the most commonly used ORM (76.7%). CONCLUSION: The development of practical and efficient ORM for lateral canal BPPV with ageotropic nystagmus is necessary.
Surveys and Questionnaires ; Delivery of Health Care ; Dizziness ; Electronic Mail ; Korea ; Otolaryngology ; Otolithic Membrane ; Public Opinion ; Vertigo