Kyoung Ho Oh

The Benefits and Risks of Prophylactic Central Neck Dissection for Papillary Thyroid Carcinoma: Prospective Cohort Study.

Objectives. This study evaluated the benefits of performing prophylactic central neck dissection (CND) with total thyroidectomy (TT) in management of papillary thyroid carcinoma (PTC) patients who were clinically node-negative at presentation. Methods. A total of 257 patients with stage T1 or T2 PTC and without preoperative evidence of lymph node involvement (N0) were enrolled in this prospective study. The patients were randomly assigned to two groups: (1) a total thyroidectomy (TT) group (n = 104) or (2) a TT plus CND group (n = 153). The two groups were compared for their perioperative data, complication rates, disease recurrence rates, and clinical outcomes. Results. The two groups of patients were similar in age, sex ratio, follow-up duration, and tumor size (P = 0.227, 0.359, 0.214, and 0.878, resp.). The two groups showed similar rates of disease recurrence (3.9% in the TT group versus 3.3% in the TT plus CND group); however, complications occurred more frequently in the TT plus CND group; especially transient hypocalcemia (P = 0.043). Conclusions. Patients treated with TT plus CND had a higher rate of complications with similar recurrence rate. We believe that CND may not be routinely recommended when treating patients with PTC.

Overexpression of the superoxide anion and NADPH oxidase isoforms 1 and 4 (NOX1 and NOX4) in allergic nasal mucosa.

Background The purpose of this study was to investigate the expression and distribution of superoxide anion, NADPH oxidase (NOX)1, and NOX4 in healthy, allergic nasal mucosa and nasal polyps to evaluate the possible influence of oxidative stress on the development of allergic rhinitis and nasal polyps. Methods The expression and distribution of superoxide anion, NOX1 and NOX4 were evaluated in healthy and allergic nasal mucosa and nasal polyps, using dihydroethidium fluorescence, semiquantitative reverse transcriptase-polymerase chain reaction, immunohistochemistry, and Western blot. Results NOX1 and NOX4 were localized mainly in the epithelial layer, submucosal glands, vascular endothelium, and inflammatory cells in healthy and allergic nasal mucosa and nasal polyps. The cellular source that generated superoxide anion is also localized in the epithelial cells, submucosal glands, vascular endothelium, and inflammatory cells, demonstrating the similar sites of expression of NOX1 and NOX4 in healthy and allergic nasal mucosa and nasal polyps. NOX1 and NOX4 mRNA and proteins and superoxide anions had increased levels of expression in allergic nasal mucosa and nasal polyps compared with healthy nasal mucosa. Conclusions These results indicate that NOX1 and NOX4 may play an important role in reactive oxygen species production, contributing to the oxidative stress in allergic rhinitis and nasal polyp tissues.

Can we use electrocochleography as a clinical tool in the diagnosis of Meniere’s disease during the early symptomatic period?

Abstract Conclusion: Our results indicate that electrocochleography (ECoG) has limited value in diagnosing Meniere’s disease during the early symptomatic period. Objective: We hypothesized that if endolymphatic hydrops is a cause of Meniere’s disease, ECoG results obtained in normal subjects would differ from those obtained during the early symptomatic period of Meniere’s disease. We aimed to investigate the usefulness of ECoG in the diagnosis of Meniere’s disease during the early symptomatic period. Methods: Extratympanic ECoG was used to evaluate 60 patients in a Meniere’s group (17 men, 43 women; mean age 43.6 years, range 19–62 years) and 30 controls (11 men, 19 women; mean age 43.5 years, range 21–63 years). The summating potential/action potential (SP/AP) amplitude ratio and SP/AP area ratio were compared between the groups. Results: Statistically significant differences were not demonstrated in the SP/AP amplitude ratio between the definite Meniere’s, probable Meniere’s, overall Meniere’s, or control groups (0.35 ± 0.02, 0.30 ± 0.03, 0.33 ± 0.02, and 0.30 ± 0.01, respectively). Additionally, statistically significant differences were not indicated in the mean SP/AP area ratio between the definite Meniere’s, probable Meniere’s, overall Meniere’s, or control groups (5.18 ± 0.98, 4.78 ± 0.21, 4.01 ± 0.78, and 3.72 ± 0.66, respectively).

Expression and distribution patterns of the stem cell marker, nestin, and the stem cell renewal factor, BMI-1, in normal human nasal mucosa and nasal polyps

Conclusions: These results suggest that nestin and BMI-1 are candidates for stem cell markers and renewal factors in human nasal mucosa, may contribute to tissue homeostasis and differentiation in the epithelium and submucosal glands of normal nasal mucosa, and may play a role in proliferation of nasal polyps. Objectives: The stem cell marker, nestin, and the stem cell renewal factor, BMI-1, have been identified in a variety of inflammatory and normal tissues, implicating these markers in tissue regeneration. Materials and methods: We investigated the expression and distribution of nestin and BMI-1 in normal nasal mucosa and nasal polyps, using RT-PCR, immunohistochemistry, and Western blotting. Results: Nestin and BMI-1 were localized to the epithelium and submucosal glands of normal nasal mucosa and nasal polyps. The expression of nestin was confined to the plasma membrane and cytoplasm, whereas BMI-1 showed a nuclear staining pattern. In normal nasal mucosa and nasal polyps, nestin and BMI-1 expression was strongest in the basal portion of the epithelial layer, and decreased toward the upper portion. In the submucosal glands, weak to strong expression was commonly detected in the glandular acini. There was no significant difference in the level of expression of nestin and BMI-1 between normal nasal mucosa and nasal polyps.

Down-Regulation of Carbonic Anhydrase Isoenzymes in Nasal Polyps

Objectives/Hypothesis: Carbonic anhydrase (CA) is a zinc metalloenzyme that participate in the biological processes of various fluid transporting epithelia, including ion and water transport. CA may thus play a role in the pathophysiology of normal nasal mucosa and nasal polyp. We evaluated the expression and pattern of distribution of mRNAs and proteins for CA isoenzymes in normal nasal mucosa and polyps.

Analysis of Temporal Change in Voice Quality After Thyroidectomy: Single-institution Prospective Study

OBJECTIVES This study analyzed the temporal changes of voice quality after thyroidectomy and assessed the predictive perioperative parameters of postthyroidectomy voice disorder (PTVD). STUDY DESIGN This is a prospective cohort study. METHODS From March 2011 to July 2014, 559 patients who underwent thyroidectomy with or without central neck dissection were prospectively enrolled. All patients underwent prospective voice evaluation using the subjective and objective comprehensive battery of assessments, preoperatively and postoperatively at 1 week, 1 month, 3 months, 6 months, and 12 months. RESULTS Fundamental frequency (F0) was not significantly decreased during the postoperative follow-up. Maximal vocal pitch (MVP) and maximal intensity were not recovered, even at 1 year postoperatively, whereas the Grade, Roughness, Breathiness, Asthenia, Strain scale reached preoperative value at postoperative 3-6 months and voice handicap index at 1 year. Postoperative 1-month MVP was the best predictor for PTVD, and the cut-off value was 80% of preoperative value. Wide surgical extent and high preoperative F0 were the parameters that significantly correlated with PTVD (P = 0.021 and P < 0.001, respectively), and large tumor, higher preoperative MVP, and lower postoperative 1-month F0 were significantly associated with permanent PTVD (P = 0.028, P < 0.001, and P = 0.003, respectively). CONCLUSIONS Different recovery patterns of voice parameters should be considered in preoperative counseling. Intensive voice therapy may be needed for patients with the ability to produce higher pitch than normal preoperatively and wide surgical extent.

Role of laminin 332 in lymph node metastasis of papillary thyroid carcinoma

OBJECTIVE The invasiveness of papillary thyroid carcinoma (PTC), including the occurrence of cervical lymph node metastasis, is the main determining factors contributing to recurrence and poor prognosis. Laminin 332 is a glycoprotein involved in cell migration and cancer cell invasion into surrounding tissues and is therefore related to poor prognosis in many cancers. Here, we investigated the expression and role of laminin 332 in PTC and examine the possibility that laminin 332 could be involved in the invasiveness of PTC. METHODS Laminin 332 expression was determined by immunohistochemical staining in all 40 patients. The correlations between laminin 332 expression and clinical factors were investigated. We examined the expression of the laminin 332 γ2 chain using reverse transcription polymerase chain reaction and western blotting in PTC cells and determined the relationship between the expression of laminin 332 and the invasiveness of these cell lines using cell invasion assays. RESULTS Laminin 332 was expressed specifically within tumor tissue. The frequency of laminin 332 γ2 chain expression was significantly correlated with cervical lymph node metastasis (​p=0.003). Invasiveness increased as the expression of laminin 332 γ2 increased in the tested PTC cell lines. CONCLUSION Laminin 332 expression may be a useful marker for predicting lymph node metastasis in papillary thyroid carcinoma, and could increase the ability of cancer cells to invade, which would influence the prognosis of patients with PTC.

Embryotoxicity and hair cell toxicity of silver nanoparticles in zebrafish embryos

OBJECTIVES The purpose of the present study was to evaluate silver nanoparticles (AgNP)-induced embryotoxicity and hair cell toxicity during zebrafish development. METHODS We exposed zebrafish embryos to various AgNP concentrations (30, 60, 120, and 240nM) and evaluated embryotoxicity at 72h and ototoxicity at 120h. Embryotoxicity parameters including abnormal morphology, mortality, hatching rate, and heart rate were investigated. Hair cells within four neuromasts were evaluated. In the present study, the average number of hair cells of zebrafish exposed to AgNP was compared with that of an unexposed control group. RESULTS The hatching rate was not significantly different between groups (control: 90%; AgNP 240nM: 89%). The control group showed 2% mortality and 0% teratogenicity, while the AgNP 240nM group showed increased mortality (11%) and teratogenicity (15%) at 72h (n=100). The heart rate of AgNP-exposed embryos tended to be lower than that of the control group (n=38). Furthermore, AgNP induced apoptotic hair cell damage in the neuromasts (control: 50.7±7.4 cells; 240nM AgNP: 41.1±6.3 cells, n=23). TUNEL positive cell counts increased significantly as AgNP concentration increases (p<0.001, n=20 in each group). CONCLUSIONS The results of this study indicate that AgNP exposure causes embryotoxicity and hair cell toxicity in zebrafish embryos.

Clinicopathologic factors associated with recurrence in low- and high-grade parotid cancers

The purpose of this study was to determine clinicopathological correlates of outcome among patients with parotid gland cancer.

Sodium Selenite Acts as an Otoprotectant against Neomycin-Induced Hair Cell Damage in a Zebrafish Model

Sodium selenite is a trace element essential for many physiological functions in the body. It is involved in various biological processes; it acts as a cofactor for antioxidant enzymes that protect against free radicals and is reported to limit metal-mediated oxidative DNA damage. In the present study, we investigated the effect of sodium selenite on neomycin ototoxicity in wild-type and transgenic zebrafish (Brn3C: EGFP). Five or six days post-fertilization, zebrafish larvae were co-exposed to 125 μM neomycin and various concentrations (10 μM, 100 μM, 250 μM, and 500 μM) of sodium selenite for 1 h. Hair cells within neuromasts of the supraorbital (SO1 and SO2), otic (O1), and occipital (OC1) lateral lines were analyzed by fluorescence microscopy (n = 10 fish per treatment). Hair cell survival was estimated as the ratio of the hair cell numbers in each group compared to those of the control group that were not exposed to neomycin. Apoptosis and hair cell damage of neuromasts were evaluated using the terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-biotin nick end labeling (TUNEL) assay and 2-[4-(dimethylamino) styryl]-N-ethylpyridinium iodide (DASPEI) assay, respectively. Ultrastructural changes were evaluated using scanning electron microscopy and transmission electron microscopy. Neuromast hair cells were preserved in zebrafish exposed to 125 μM neomycin and 500 μM sodium selenite for 1 h. Sodium selenite protected against neomycin-induced hair cell loss of neuromasts, reduced apoptosis, and prevented zebrafish ultrastructural changes. We propose that sodium selenite protects against neomycin-induced hair cell damage by inhibiting apoptosis, decreasing the disarray of stereocilia, and preventing ultrastructural changes in the neuromast hair cells of the zebrafish.