Effects of endogenous and exogenous oestrogen exposure on hearing level in postmenopausal women: A cross-sectional study.

OBJECTIVE: To investigate the effect of endogenous and exogenous oestrogen exposure on hearing levels in postmenopausal women. STUDY DESIGN: Retrospective cross-sectional study. SETTING: Population-based survey data collected by the Korean National Health and Nutrition Survey between 1 January 2010 and 31 December 2012. SUBJECTS AND METHODS: Participants comprised 3653 postmenopausal women. Detailed histories for reproductive factors and data on the use of hormone replacement therapy were obtained through health questionnaires and otologic examinations, including pure-tone audiogram and otoscopic findings. Complex-sample linear regression models controlling for confounding factors were generated to determine whether hormone-related factors were associated with hearing loss. RESULTS: Women who experienced a longer duration of oestrogen exposure had better hearing compared to those who do not in multivariate model adjusting for confounding factors with a lower adjusted beta coefficient of hearing threshold (ß = -0.18, 95% confidence interval = -0.3 to -0.07, P = .002). The results also suggested that hormone replacement therapy may be beneficial for attenuating hearing loss (ß = -1.22, 95% confidence interval = -2.19 to -0.25, P = .014), particularly in the high-frequency range from 3 to 6 KHz. CONCLUSION: A longer duration of lifetime oestrogen exposure (LEE) and the use of hormone replacement therapy are likely to attenuate hearing loss. These epidemiologic data provide evidence that oestrogen may be beneficial for attenuating age-related hearing decline.

Trends in Distributions of Hearing Threshold Levels by Ages: A Comparison of the ISO 7029 and Newly Available Country-Specific Data.

Hearing thresholds provide essential information and references about the human auditory system. This study aimed to identify changing trends in distributions of hearing threshold levels across ages by comparing the International Organization for Standardization (ISO) 7029 and newly available data after publishing ISO 7029. To compare ISO 7029 and newly available hearing threshold data after publishing ISO 7029, four country-specific datasets that presented average hearing threshold levels under conditions similar to ISO 7029 were utilized. For frequencies between 125 Hz and 8,000 Hz, the deviations of hearing threshold values by ages from the hearing threshold of the youngest age group for each data point were utilized. For frequencies from 9,000 Hz to 12,500 Hz, the median threshold information was utilized. Hearing threshold data reported after publishing ISO 7029 from the four countries were mostly similar to the ISO 7029 data but tended to deviate in some age groups and sexes. As national hearing threshold trends change, the following ISO 7029 revision suggests the need to integrate hearing threshold data from different countries.

Association of balance impairment with risk of incident cardiovascular diseases among older adults.

BACKGROUND: Rapid decline in balance is a hallmark of aging, elevating the risk of falls and other age-related geriatric illnesses among older adults. OBJECTIVE: Our aim was to assess whether impairment in balance function is associated with the risk of incident CVD in older adults. DESIGN: Retrospective cohort analysis. PARTICIPANTS: A total of 129,024 participants who had undergone health screening between 2002 and 2009 were derived from the National Health Insurance Service-Senior cohort. MAIN MEASURES: Balance impairment was evaluated using the open-eyes one-leg standing (OLS) test. The association between balance impairment and incident CVD was analyzed using the Cox proportional hazards regression model. All participants were followed up with until either the date of the first incident of CVD, death, or 31 December 2019. KEY RESULTS: Those with abnormal balance function (< 10 s in OLS test) had a higher risk of CVD (adjusted hazard ratio [aHR] 1.23, CI 1.16-1.31). The association was significant in both the obese and the non-obese, but it seemed to be more pronounced in the latter. Results were supported by sensitivity analyses that did not include cases of CVD development in the first 1, 2, or 3 years and that used a different criterion to define balance dysfunction (< 9 s in OLS test). CONCLUSIONS: Older adults with balance impairment were found to have an increased risk of incident CVD. Patients with impaired balance function may be a high-risk population who require preventive managements against CVD.

Association Between Hearing Impairment and Incident Depression: A Nationwide Follow-up Study.

BACKGROUND: Accumulating evidence suggests that hearing impairment is associated with the onset of depression. However, large-scale epidemiological studies are required to define this association more clearly. We aimed to investigate the risk of new-onset depression in Korean older adults with and without hearing impairment. METHODS: From the National Health Insurance Service-Senior Cohort, which is a retrospective-prospective hybrid database, we analyzed data for 254,466 older adults enrolled in the Korea National Health Insurance Service-Senior Cohort who underwent at least one health screening between 2003 and 2019. A Cox proportional hazards regression model was used to evaluate the association between hearing impairment and the risk of incident depression, which was presented as adjusted hazard ratios (aHR) with 95% confidence intervals (CIs). All participants were followed up until the date of incident depression, death, or December 31, 2019. RESULTS: During 3,417,682 person-years of follow-up investigation, hearing impairment was associated with a higher risk of incident depression (vs. no hearing impairment) in the final adjusted model (aHR, 1.11; 95% CI, 1.01-1.21; p = 0.033). Stratified analyses revealed a significant interaction among age, hearing impairment, and the risk of depression. Participants aged <65 years had a higher risk of depression (aHR, 1.29; 95% CI, 1.12-1.50; p < 0.001) than those aged 65 or above (aHR, 1.15; 95% CI, 1.01-1.30; p = 0.032). CONCLUSIONS: Hearing impairment is independently associated with a higher risk of depression among older adults. The prevention and treatment of hearing impairment may aid in mitigating the risk of incident depression. LEVEL OF EVIDENCE: Level 3 Laryngoscope, 133:3144-3151, 2023.

Improving Accuracy and Reliability of Hearing Tests: An Exploration of International Standards.

This study explores the internal standards for hearing tests and benefits of implementing international standard protocols, including the International Organization for Standardization (ISO) and International Electrotechnical Commission (IEC), and discusses how ISO and IEC standards provide a framework for designing, calibrating, assessing hearing test instruments and methods, and exchanging and comparing data globally. ISO and IEC standards for hearing tests improve accuracy, reliability, and consistency of test results by applying standardized methods and environments. Moreover, they promote international harmonization and data interoperability, enabling information exchange and research collaboration. Those standards for hearing tests are beneficial but have challenges and limitations, such as variation in equipment and calibration, lag in updating standards, variation in implementation and compliance, and lack of coverage of clinical aspects, cultural diversity, and linguistic diversity. These affect the quality and interpretation of test results. Adapting ISO or IEC standards locally would improve their applicability and acceptability, while balancing customization and compatibility with global standards.

Atypical Fibroxanthoma Resected without Auricular Deformity in an Elderly Patient: A Case Study.

Atypical fibroxanthoma (AFX) is a dermal spindle-cell cutaneous malignancy, which is a relatively benign type of skin cancer that occurs in the elderly with sun-damaged skin. This is a case study of a rapidly enlarged left auricular mass lesion in an elderly patient who was diagnosed with AFX based on histopathological and immunohistochemical findings, and then treated by complete excision to prevent recurrence or metastasis. There was no recurrence during the 1-year follow-up. For otolaryngologists or plastic surgeons, recognizing the clinical and pathologic characteristics of AFX is important for accurate diagnosis and treatment.

Is Body Mass Index Related to Skin Reactivity to Histamine but not to Specific Allergens? A 2-Year Follow-up Study on Korean Children.

BACKGROUND: Skin prick tests are widely used to diagnose allergic sensitization. The influence of obesity on the skin prick test result has not been clearly established, even though the association between allergic disease and obesity is relatively well known. OBJECTIVE: To determine whether a change in body mass index (BMI) contributes to skin reactivity to histamine and allergens in a skin prick test, we performed a 2-year follow-up study on Korean children. METHODS: Skin prick tests for common aeroallergens were performed on elementary school students from Jeju Island, Korea. BMI was calculated using weight and height after measuring both, and demographic characteristics were surveyed. The same tests were repeated after 2 years. RESULTS: The sensitization rate increased during the 2 years between tests and the children's mean BMI also increased, along with their age. The wheal sizes induced by Dermatophagoides pteronyssinus, Dermatophagoides farinae, Japanese cedar, and histamine were significantly increased during 2 years; however, only the histamine reaction associated with increased BMI had statistical significance. Furthermore, other variables-including the number of sensitized allergens-were not related to histamine skin reactivity. CONCLUSION: Histamine skin reactivity increased in children over time and some allergens showed increased specific reactions; however, BMI gain is a specific predictor of histamine reactivity. Further studies are needed to elucidate the clinical significance of these changes.

The Association between the Concentration of Heavy Metals in the Indoor Atmosphere and Atopic Dermatitis Symptoms in Children Aged between 4 and 13 Years: A Pilot Study.

BACKGROUND: A correlation between the harmful effects of air pollutants and atopic dermatitis has been reported. There are few studies on the correlation between the concentration of heavy metals in the indoor atmosphere and symptoms of atopic dermatitis. METHODS: Twenty-two homes of children showing atopic dermatitis symptoms were enrolled, and eighteen homes with similarly aged children without symptoms or a history of atopic dermatitis participated as a control group. We measured the concentrations of various air pollutants (particulate matter 10, carbon dioxide, carbon monoxide, formaldehyde, nitrogen dioxide, volatile organic compounds (VOCs), ozone, radon, bacterial aerosols, and mold) as well as various heavy metals, such as lead, cadmium, and mercury, in the living room and children's bedroom of each home. RESULTS: Lead was more commonly detected in the indoor air in houses of children with atopic dermatitis (15/22) as compared to in the control group (3/18) (chi square test, p = 0.002). In adjusted logistic regression analysis, VOCs and lead were significantly associated with atopic dermatitis (p < 0.05). CONCLUSION: Our study shows that lead in indoor air might be associated with atopic dermatitis, even if the concentrations of airborne lead are below the safety levels suggested by health guidelines.

Is Ossiculoplasty Necessary in Canal Wall Down Mastoidectomy? Comparison of Clinical Outcomes Between Type 0 Tympanoplasty and Ossiculoplasty.

BACKGROUND AND OBJECTIVES: To assess whether the audiological and clinical outcomes of type 0 tympanoplasty (T0) performed using cartilage were comparable with those of ossiculoplasty in patients who underwent canal wall down mastoidectomy (CWDM). SUBJECTS AND METHODS: This study included patients who had chronic otitis media with cholesteatoma and underwent CWDM with ossiculoplasty involving partial ossicular replacement prosthesis (PORP), total ossicular replacement prosthesis (TORP), or T0. Anatomical success rates and hearing outcomes were analyzed. RESULTS: Seventy-two patients were included in this study; 29 of them underwent CWDM with T0, 27 underwent CWDM with PORP, while 16 underwent CWDM with TORP. The difference in mean improvement in the air-bone gap (ABG) between the groups was not significant. The differences in the rates of ABG closure to ≤10 dB HL (p=0.030) and ≤20 dB HL (p=0.029) were significant. There were significant differences in improvements in the ABG at 3 kHz among the PORP, TORP, and T0 groups. CONCLUSIONS: The audiological outcomes of CWDM with ossiculoplasty seemed to be better than those of CWDM with T0 with no significant difference in the incidence of complications following ossiculoplasty and T0.

Hazardous Alcohol Consumption and the Risk of Hearing Impairment in Adults Based on the Korean National Health and Nutrition Survey: A Retrospective Study.

BACKGROUND AND OBJECTIVES: To investigate the relationship between hearing impairment and alcohol drinking patterns in South Korean adults. SUBJECT AND METHODS: Data collection was performed by Korean National Health and Nutrition Survey from January 1 to December 31, 2012. Data analyses were performed from February 20 to March 3, 2018. Data from 3,860 adults 20 years of age or older without a history of malignancy or chronic otitis media in the Korean National Health and Nutrition Survey 2012 database who participated in the health questionnaires, and who had available results from otologic examinations that included pure tone audiogram, were included. Pure-tone average hearing thresholds were calculated at 500, 1,000, 2,000, and 4,000 Hz. Hearing loss was defined as a pure-tone average >40 dB in one or both ears. The Alcohol Use Disorder Identification Test was used to evaluate drinking statuses of subjects. Data were analyzed using the complex-sample χ2 -test of independence and a complex-sample logistic regression analysis. RESULTS: Of the 29,954,319 individuals in the weighted cross-sectional study population, 15,106,040 (50.4%) were men and 14,848,098 (49.6%) were women. A total of 8.1% of men and 7% of women had hearing impairment. The degrees of drinking with appropriate, risky, and hazardous drinking habits were 58.2, 32.1, and 9.7% among men; and 76.4, 12.5, and 11.1% among women, respectively. Among men, the odds ratio of hearing loss increased by 2.506 times when comparing hazardous and appropriate drinking (confidence interval, 1.083 to 5.800, p=0.002). Moderate alcohol consumption (≤2 drinks per day) was not protective for hearing in either group. CONCLUSIONS: As hazardous drinking tends to coexist with hearing impairment in men, appropriate prevention and intervention strategies should be emphasized. A longitudinal study to investigate harmful drinking and the mechanism of hearing loss should be performed.

Comparison of clinical outcomes between butterfly inlay cartilage tympanoplasty and conventional underlay cartilage tympanoplasty.

OBJECTIVE: To assess the efficacy of butterfly inlay cartilage tympanoplasty and compare it with conventional underlay cartilage tympanoplasty in terms of success rate and hearing outcomes. MATERIALS AND METHODS: The study included 35 patients (36 ears) who underwent butterfly inlay cartilage tympanoplasty (inlay group, 23 ears of 22 patients) or conventional underlay cartilage tympanoplasty (underlay group, 13 ears). The anatomical success rate and hearing outcomes were analysed. RESULTS: Re-perforation occurred in 2 cases (8.7%) in the inlay group and 3 (23.1%) in the underlay group. One patient in the inlay group developed a serious infection, and one in the underlay group developed massive granulation of the tympanic membrane. In the inlay group, the air-bone gap (ABG) decreased from 19.9 (±12.6) dB HL preoperatively to 13.8 (±11.3) dB HL postoperatively (p=0.047), in the underlay group, it decreased from 23.5 (±15.8) dB HL to 18.3 (±20.6) dB HL. Regarding improvement in ABG, the difference between the group was not statistically significant (p=0.968). CONCLUSION: Butterfly inlay cartilage tympanoplasty is comparable with conventional underlay cartilage tympanoplasty in both anatomic and audiological success rates. Owing to its simplicity, shorter operation time, and rapid patient recovery, butterfly inlay cartilage tympanoplasty could be considered a favourable surgical option.

Clinical Characteristics of Bilateral Meniere's Disease in a Single Asian Ethnic Group.

OBJECTIVES/HYPOTHESIS: To identify the clinical characteristics of patients with bilateral Meniere's disease (MD) in an Asian population. STUDY DESIGN: Cross-sectional retrospective study. METHODS: We compared the clinical features of bilateral MD (BMD) and unilateral MD (UMD) in 320 Asian patients with single ethnicity. Demographic variables; age of onset; inner ear function; the coexistence of related disorders such as vestibular migraine, delayed MD, systemic autoimmune diseases, and familial MD; and prognoses were analyzed and compared. RESULTS: The overall prevalence of BMD was 5.6%. The mean age of disease onset was 40.3 ± 14.8 and 47.0 ± 14.1 years for patients with BMD and UMD, respectively (P = .07). Demographic variables were not significantly different between patients with BMD and UMD (P > .05). Inner ear function, evaluated by hearing thresholds, caloric tests, and cervical vestibular evoked myogenic potentials, was significantly more deteriorated in the first involved ear of patients with BMD than in the second involved ear or the affected side of patients with UMD (P < .05). Among the comorbid conditions, only the prevalence of delayed MD was significantly higher in patients with BMD than in patients with UMD. Systemic autoimmune disease was found in only three patients with UMD. There was no significant prognostic difference between patients with UMD and BMD (P > .05). CONCLUSIONS: A low prevalence of BMD, a higher frequency of delayed MD in BMD patients, and a low frequency of systemic autoimmune diseases in both UMD and BMD patients are significant findings in an Asian population. LEVEL OF EVIDENCE: 4 Laryngoscope, 129:1191-1196, 2019.

Number of seasonal exposures to Japanese cedar pollen increases the risk of sensitization: Observational study in Korean adults.

Sensitization to seasonal allergens usually requires repeated exposure to them. However, research on the extent of exposure that increases the risk of sensitization to specific allergens is lacking. Therefore, we investigated the levels of exposure to Japanese cedar pollen that increased the risk of sensitization to it. A cross-sectional study was conducted with 857 college students living in Jeju, South Korea, as it is the only province in Korea where Japanese cedar pollen levels are high. Questionnaires about demographic characteristics were distributed and skin prick tests for allergic sensitization were performed. Sensitization rates of groups divided by residence period were 3.8% (less than 1 year), 1.8% (1-2 years), 8.5% (2-3 years), 10.3% (3-4 years), 14.8% (4-10 years), and 19.1% (over 10 years). Residence period was an influencing factor of sensitization rate to Japanese cedar pollen, and the cut-off value of the residence period that increased the risk of sensitization to Japanese cedar pollen was found to be 25 months. Repeated exposure to seasonal allergens was related to an increased sensitization rate in young adults. Our results suggested that exposure to Japanese cedar pollen for over two seasons could increase the risk in Korean adults.

Chronological changes in rhinitis symptoms present in school-aged children with allergic sensitization.

INTRODUCTION: It is difficult to accurately predict the natural course of allergic rhinitis (AR), because it is affected by a wide variety of environmental influences, as well as genetic predisposition. Considering the high prevalence of allergic rhinitis in children and adolescents, caregivers should be given appropriate information regarding the disease course. This study aimed to understand the prognosis of allergic rhinitis by examining the relationship between allergic sensitization and rhinitis symptoms during this developmental period. METHODS: This cross-sectional study included 1069 children aged 9-16 years from the Korean International Study of Asthma and Allergies in Childhood Survey database who had completed health questionnaires, and for whom skin prick test results were available. Data were collected during May 2016. The distribution of sensitization and allergic symptoms was compared by age groups (elementary, middle, and high school). Data were analyzed using linear-by-linear analysis. RESULTS: Sensitization to at least one tested allergen differed by age (59.2%, 58.3%, 68.2%, in elementary, middle, and high school students, respectively; p = 0.025), and seasonal allergen sensitization (35.0%, 37.1%, 53.9%, respectively) increased with age (p < 0.001). Conversely, the proportion of rhinitis symptoms among sensitized children decreased as age increased (58.80%, 52.90%, 49.70%, respectively; p = 0.047). However, the rate of non-allergic rhinitis was age-independent. CONCLUSION: With increasing age during childhood and adolescence, symptomatic allergic rhinitis decreases; thus, subclinical allergic rhinitis increases. This suggests that the symptoms of later-sensitized children are less clearly manifested, or that the symptoms reduce as previously sensitized children mature. This should be clarified further in a longitudinal study.

Anti-tumor effects of cold atmospheric pressure plasma on vestibular schwannoma demonstrate its feasibility as an intra-operative adjuvant treatment.

Vestibular schwannoma (VS), although a benign intracranial tumor, causes morbidities by brainstem compression. Since chemotherapy is not very effective in most Nf2-negative schwannomas, surgical removal or radiation therapy is required. However, depending on the size and site of the tumor, these approaches may cause loss of auditory or vestibular functions, and severely decrease the post-surgical wellbeing. Here, we examined the feasibility of cold atmospheric pressure plasma (CAP) as an intra-operative adjuvant treatment for VS after surgery. Cell death was efficiently induced in both human HEI-193 and mouse SC4 VS cell lines upon exposure to CAP for seven minutes. Interestingly, both apoptosis and necroptosis were simultaneously induced by CAP treatment, and cell death was not completely inhibited by pan-caspase and receptor-interacting serine/threonine-protein kinase 1 (RIK1) inhibitors. Upon CAP exposure, cell death phenotype was similarly observed in patient-derived primary VS cells and tumor mass. In addition, CAP exposure after the surgical removal of primary tumor efficiently inhibited tumor recurrence in SC4-grafted mouse models. Collectively, these results strongly suggest that CAP should be developed as an efficient adjuvant treatment for VS after surgery to eliminate the possible remnant tumor cells, and to minimize the surgical area in the brain for post-surgical wellbeing.

Discrepancies between video head impulse and caloric tests in patients with enlarged vestibular aqueduct.

OBJECTIVE: We performed the video head impulse test (vHIT) and caloric test in patients with enlarged vestibular aqueducts (EVA). We compared the results with those found in Ménière's disease (MD) and acute vestibular neuritis to clarify the characteristics of vestibular dysfunction in EVA and to suggest reasons for the discrepancy between the vHIT and caloric tests in endolymphatic hydrops. STUDY DESIGN: Retrospective analysis. METHODS: Ten patients with EVA and confirmed biallelic SLC26A4 genetic mutations were enrolled. The results of video head impulse and caloric tests were analyzed and compared with those of patients diagnosed with MD (n = 76) or acute vestibular neuritis (n = 19). RESULTS: Among patients with EVA, 40% showed unilateral caloric weakness and 30% had recurrent episodes of vertigo. All patients with recurrent vertigo had caloric weakness. However, only 25% of patients with abnormal caloric test results had abnormal vHIT results. The discrepancy between the caloric test and vHIT results was also found in patients with MD, but not in patients with acute vestibular neuritis (abnormal vHIT results in 47.3% and 94.7% of patients with unilateral caloric weakness, respectively). CONCLUSION: Unilateral vestibular dysfunction was identified in 40% of patients with EVA by the caloric test, but caloric test results were not correlated with vHIT results. This finding was similar in patients with MD. Hence, it is possible that endolymphatic hydrops, a common pathologic feature of both EVA and MD, could cause the discrepancy, and that vestibulopathy in endolymphatic hydrops might be restricted to the low-frequency range. LEVEL OF EVIDENCE: 4. Laryngoscope, 127:921-926, 2017.

Effects of Saccular Function on Recovery of Subjective Dizziness After Vestibular Rehabilitation.

OBJECTIVE: We attempted to investigate whether the integrity of saccular function influences the severity of subjective dizziness after vestibular rehabilitation in vestibular neuritis. STUDY DESIGN: Retrospective analysis. SETTING: Tertiary referral center. PATIENTS: Forty-six patients with acute unilateral vestibular neuritis were included. INTERVENTIONS: Diagnostic, therapeutic, and rehabilitative. MAIN OUTCOME MEASURES: All the patients completed vestibular rehabilitation therapy until their computerized dynamic posturography and rotary chair test results were significantly improved. The rehabilitation patients were classified into the normal to mild subjective dizziness and moderate to severe subjective dizziness groups according to the dizziness handicap inventory score (cutoff of 40). Differences between the two groups were analyzed. RESULTS: After rehabilitation, 32.6% of the patients still complained of moderate to severe dizziness. Age, sex distribution, the presence of comorbidities, caloric weakness, pre- and postrehabilitation gain values in rotary chair test, postrehabilitation composite scores in posturography, and the duration of rehabilitation were not significantly different between the two groups. However, initial dizziness handicap inventory (DHI) score and composite score in dynamic posturography were worse and the proportion of patients with absent cervical vestibular-evoked myogenic potential in the moderate to severe group was much higher (93.3% vs. 35.5%, p < 0.001). After multiple regression analysis of those factors, initial DHI score and absent cervical vestibular-evoked myogenic potential response were identified as being associated with higher postrehabilitation DHI score. CONCLUSION: Saccular dysfunction in acute vestibular neuritis can contribute to persistent subjective dizziness, even after the objective parameters of vestibular function tests have been improved by vestibular rehabilitation.

Electrogenic transport and K(+) ion channel expression by the human endolymphatic sac epithelium.

The endolymphatic sac (ES) is a cystic organ that is a part of the inner ear and is connected to the cochlea and vestibule. The ES is thought to be involved in inner ear ion homeostasis and fluid volume regulation for the maintenance of hearing and balance function. Many ion channels, transporters, and exchangers have been identified in the ES luminal epithelium, mainly in animal studies, but there has been no functional study investigating ion transport using human ES tissue. We designed the first functional experiments on electrogenic transport in human ES and investigated the contribution of K(+) channels in the electrogenic transport, which has been rarely identified, even in animal studies, using electrophysiological/pharmacological and molecular biological methods. As a result, we identified functional and molecular evidence for the essential participation of K(+) channels in the electrogenic transport of human ES epithelium. The identified K(+) channels involved in the electrogenic transport were KCNN2, KCNJ14, KCNK2, and KCNK6, and the K(+) transports via those channels are thought to play an important role in the maintenance of the unique ionic milieu of the inner ear fluid.

Hypoxia Induces Epithelial-Mesenchymal Transition in Follicular Thyroid Cancer: Involvement of Regulation of Twist by Hypoxia Inducible Factor-1α.

PURPOSE: Although follicular thyroid cancer (FTC) has a relatively fair prognosis, distant metastasis sometimes results in poor prognosis and survival. There is little understanding of the mechanisms contributing to the aggressiveness potential of thyroid cancer. We showed that hypoxia inducible factor-1α (HIF-1α) induced aggressiveness in FTC cells and identified the underlying mechanism of the HIF-1α-induced invasive characteristics. MATERIALS AND METHODS: Cells were cultured under controlled hypoxic environments (1% O2) or normoxic conditions. The effect of hypoxia on HIF-1α, and epithelial-to-mesenchymal transition (EMT) related markers were evaluated by quantitative real-time PCR, Western blot analysis and immunocytochemistry. Invasion and wound healing assay were conducted to identify functional character of EMT. The involvement of HIF-1α and Twist in EMT were studied using gene overexpression or silencing. After orthotopic nude mouse model was established using the cells transfected with lentiviral shHIF-1α, tissue analysis was done. RESULTS: Hypoxia induces HIF-1α expression and EMT, including typical morphologic changes, cadherin shift, and increased vimentin expression. We showed that overexpression of HIF-1α via transfection resulted in the aforementioned changes without hypoxia, and repression of HIF-1α with RNA interference suppressed hypoxia-induced HIF-1α and EMT. Furthermore, we also observed that Twist expression was regulated by HIF-1α. These were confirmed in the orthotopic FTC model. CONCLUSION: Hypoxia induced HIF-1α, which in turn induced EMT, resulting in the increased capacity for invasion and migration of cells via regulation of the Twist signal pathway in FTC cells. These findings provide insight into a possible therapeutic strategy to prevent invasive and metastatic FTC.

Feasibility of robot-assisted submandibular gland resection via retroauricular approach: preliminary results.

OBJECTIVES/HYPOTHESIS: To present the surgical technique and feasibility of robot-assisted submandibular gland (SMG) resection via retroauricular approach. STUDY DESIGN: Feasibility study of case series. METHODS: We performed robot-assisted SMG resection on five patients with benign SMG tumors. The surgical complications, operation time, amount of bleeding, amount and duration of drainage, and duration of hospital stay were reviewed. RESULTS: The surgery was successful in all patients without any significant complications. The mean operation time was 62.4 ± 6.3 minutes, amount of bleeding was 10.4 ± 3.2 mL, amount of drainage was 149.8 ± 114.7 mL (3.2 ± 1.6 days), and duration of hospital stay was 4.2 ± 1.8 days. All patients showed excellent cosmetic satisfaction because the postoperative scar was hidden by the auricle and hair. CONCLUSIONS: Robot-assisted SMG resection was feasible without any significant complications and satisfactory cosmetic results. The safety and oncologic outcome of the procedure should be verified with larger number of patients and longer follow up period.