Soon-Hyun Ahn

Role of core needle biopsy and ultrasonographic finding in management of indeterminate thyroid nodules

Thyroid fine‐needle aspiration (FNA) is used as a screening test of choice for evaluation of thyroid nodules. However, approximately 15% to 25% of the cases are classified as indeterminate, posing dilemmas in decision‐making. This study was designed to compare the diagnostic performances of second FNA and core needle biopsy of indeterminate nodules by initial FNA.

Speech perception after cochlear implantation over a 4-year time period.

Objective – To evaluate the long-term speech perception of cochlear implantees and to compare the developing auditory performance patterns of prelingual children and postlingual deaf adults. Material and Methods – Twenty-nine prelingually deaf children and 17 postlingually deaf adults who had been followed up for 4 years were included in the study. Speech perception ability was assessed by means of vowel and consonant confusion tests and the Korean version of the Central Institute of Deafness (K-CID) test (performed without visual cues). The test results were analyzed at 3 and 6 months after implantation and then annually. Results – In the prelingually deaf children, the average results continuously improved over the 4-year period. In the postlingually deaf adults, the average results did not improve further after the first 2 years. Individuals with <5 years of deafness had a faster rate of recovery of speech perception than those who had been deaf for >5 years. The K-CID scores were negatively correlated with age at implantation for the prelingually deaf group and with the duration of deafness in the postlingually deaf group. Children fitted with implants at a younger age showed better speech perception ability than those fitted with implants at an older age. Interestingly, prelingually deaf children aged 5–7 years at implantation showed the widest variation in individual outcomes. Amongst this group of children with highly variable outcomes, the metabolic status of brain cortices determined by means of 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) was available for three patients. The individual with the widest hypometabolic area had the best speech perception ability. Conclusion – The extent of hypometabolism as assessed by FDG-PET seemed to be one of the major factors predicting the outcome of cochlear implantation.

Elevated risk of papillary thyroid cancer in Korean patients with Hashimoto's thyroiditis†

Hashimotos thyroiditis (HT) and higher levels of thyroid‐stimulating hormone (TSH) have been proposed as risk factors for papillary thyroid cancer (PTC), but this issue is still being debated. The purpose of this study was whether HT was related to the risk of PTC over TSH.

Management of intratemporal facial nerve schwannoma.

Objective The aim of this study was to report a series of 18 facial nerve schwannomas, including 2 infantile cases. Study Design Retrospective case review. Setting Tertiary referral center. Patients Eighteen patients with facial nerve schwannoma, operated on between 1980 and 2000. Intervention Surgical treatments were performed in all cases. Main Outcome Measures The presenting symptoms and facial nerve function were graded using the House-Brackmann scale and eye closure. Results Facial nerve paralysis was the most common symptom, presenting in 94% of cases, followed by hearing loss and mass lesion. In one case, the tumor was shaved, leaving the facial nerve intact. In the other cases, the facial nerve reconstruction with hypoglossal-facial anastomosis or interposition graft was performed. The postoperative facial function was House-Brackmann grade IV in most cases (88.2%). In terms of the functional recovery classified by complete or incomplete eye closure, the moderate preoperative facial nerve palsy group showed a better functional outcome than severe group. Conclusion In cases with good facial nerve function, it would be better to consider an alternative method for preserving the facial nerve. Furthermore, when facial nerve paralysis has developed to more than House-Brackmann grade III, an immediate operation is recommended to obtain a good postoperative facial functional recovery.

Thyroid “Atypia of undetermined significance” with nuclear atypia has high rates of malignancy and BRAF mutation

“Atypia of undetermined significance” (AUS) in the Bethesda System for Reporting Thyroid Cytopathology is a heterogeneous category for cases that cannot be easily classified into benign, suspicious, or malignant. This study evaluated whether cytomorphology‐based subcategorization could better predict the malignancy risk in cases designated as AUS, and how the subcategories correlated with BRAF mutation status in thyroid fine‐needle aspirates (FNA).

Difference of delayed post-tonsillectomy bleeding between children and adults.

OBJECTIVE To analyze the characteristics of post-tonsillectomy bleeding and its management comparing with adults. METHODS A retrospective chart review of 1489 patients who underwent tonsillectomy in our institution (June 2003-June 2006). RESULTS Post-tonsillectomy bleeding rate was 3.1%, 2.5% and 10.8% in younger children (age< or =11 years), older children (12< or =age< or =15 years) and adults (age>15 years), respectively. Although adults showed an unimodal peak time for onset of post-tonsillectomy bleeding, children showed a bimodal peak time. In the younger child group, all of the 28 bleeders had spontaneous hemostasis. However, in the older child group, there was no spontaneous hemostasis. Bleeding was controlled under local anesthesia in 3 patients and 2 patients required general anesthesia for bleeding control. In the adult group, spontaneous cessation of bleeding occurred in 25 patients (60.9%) and hemostasis under local or general anesthesia was performed in 16 (39.1%) patients. CONCLUSIONS Post-tonsillectomy bleeding occurred more frequently in adults than in children. Spontaneous hemostasis was more prevalent in children than in adults. Post-tonsillectomy bleeding in the younger child group was controlled with close observation alone.

The Effects of Surface Roughness of Composite Resin on Biofilm Formation of Streptococcus mutans in the Presence of Saliva

The purpose of this study was to investigate the effects of surface roughness of resin composite on biofilm formation of Streptococcus mutans in the presence of saliva. To provide uniform surface roughness on composites, disks were prepared by curing composite against 400-grit silicon carbide paper (SR400), 800-grit silicon carbide paper (SR800), or a glass slide (SRGlass). The surface roughness was examined using confocal laser microscopy. For biofilm formation, S. mutans was grown for 24 hours with each disk in a biofilm medium with either glucose or sucrose in the presence of fluid-phase or surface-adsorbed saliva. The adherent bacteria were quantified via enumeration of the total viable counts of bacteria. Biofilms were examined using scanning electron microscopy. This study showed that SR400 had deeper and larger, but fewer depressions than SR800. Compared to SRGlass and SR800, biofilm formation was significantly increased on SR400. In addition, the differences in the effect of surface roughness on the amount of biofilm formation were not significantly influenced by either the presence of saliva or the carbohydrate source. Considering that similar differences in surface roughness were observed between SR400 and SR800 and between SR800 and SRGlass, this study suggests that surface topography (size and depth of depressions) may play a more important role than surface roughness in biofilm formation of S. mutans .

Sunitinib inhibits papillary thyroid carcinoma with RET/PTC rearrangement but not BRAF mutation.

Sunitinib, a multi-targeted tyrosine kinase inhibitor, is frequently incorporated into the management of papillary thyroid carcinoma refractory to standard therapies. Although clinical trials are in progress, the mechanism of action in papillary thyroid carcinomas is not clear, especially regarding the effect on BRAF mutation. We investigated the effect of sunitinib on papillary thyroid carcinoma cells harboring RET/PTC rearrangement and BRAF mutation using TPC-1M, SNU-790, and B-cPAP cell lines. Cell growth of papillary thyroid cancer cells with RET/PTC rearrangement was effectively inhibited at low doses of sunitinib (IC50=0.658 μM), whereas that of BRAF mutated cells required higher doses. Immunoblotting revealed effective blocking of MEK/ERK pathway in RET/PTC rearrangement cells, but not in BRAF mutated cells. Cell cycle analysis showed G1 arrest in RET/PTC rearrangement cells. In vivo orthotopic thyroid cancer mouse model demonstrated statistically significant tumor growth inhibition by sunitinib in RET/PTC rearrangement cancer cells. We conclude that sunitinib effectively inhibits RET/PTC rearrangement cells but not BRAF mutated cells. These data suggest that sunitinib exerts its effect by inhibiting the upstream MAPK signaling cascade. These findings support the unsatisfactory treatment outcomes of sunitinib in many already ongoing clinical trials compared to other tyrosine kinase inhibitors. Clinical application of sunitinib should be directed accordingly.

Effects of IL-1 beta, TNF-alpha, and TGF-beta on ciliary beat frequency of human nasal ciliated epithelial cells in vitro

Previous reports suggested that several cytokines may influence the ciliary beat of the airway ciliated epithelial cells. The aim of this study is to determine the effects of cytokines including IL-1β, TNF-α, and TGF-β on ciliary beat frequency (CBF) of human nasal ciliated epithelial cells. CBF of cultured human nasal ciliated epithelial cells was measured 24 hours after incubating with concentrations of 0.01 ng/mL, 0.1 ng/mL, 1 ng/mL, 10 ng/mL, and 100 ng/mL of each recombinant human (rh) cytokine including rhIL-1β, rhTNF-α, and rhTGF-β. CBF was measured with time at concentrations of 1 ng/mL of rhIL-1β, 10 ng/mL of TNF-α, and 1 ng/mL of TGF-β solutions. CBF of the human nasal ciliated epithelial cells increased after addition of rhIL-1β and rhTNF-α. Maximum CBF was observed at 1 ng/mL of rhIL-1β and at 10 ng/mL of rhTNF-α. CBF increased progressively to 4 hours after addition of rhIL-1β and rhTNF-α. Increased CBF sustained for 24 hours and decreased by 2 days. However, no variation of CBF was observed after addition of rhTGF-β, regardless of concentrations and time. The results of this study suggest that during acute inflammation, IL-1β and TNF-α may have a potential role in defense mechanism of human nasal epithelium by regulating CBF of the nasal ciliated epithelial cells.

HIF‐1α and HSP90: Target molecules selected from a tumorigenic papillary thyroid carcinoma cell line

It is important to properly identify aggressive tumors among differentiated thyroid cancers that are most often indolent. By comparison of a tumorigenic clone with an originally less tumorigenic papillary thyroid carcinoma (PTC) cell line, we looked for markers involved in the aggressive biology of thyroid cancer. Human PTC cell lines BHP10‐3 and its tumorigenic subclone BHP10‐3SCmice were compared using microarray analysis. Upregulated genes in the tumorigenic clone were selected for RT‐PCR, immunoblot analysis and immunohistochemistry in human tissue. Hypoxia‐inducible factor (HIF)‐1α and its chaperone protein heat shock protein (HSP)90 showed significantly increased expression in BHP10‐3SCmice and human PTC tissue. These two genes, HIF‐1α and HSP90, were further validated using siRNA gene knockdown, pharmacological inhibition using 17‐N‐allylamino‐17‐demethoxygeldanamycin (17‐AAG), an inhibitor of both HSP90 and HIF‐1α and in vivo orthotopic animal model. Invasiveness of BHP10‐3SCmice was abrogated by blockade of HIF‐1αin vitro by both siRNA and 17‐AAG. The same finding was demonstrated in the orthotopic animal model. These findings support that HIF‐1α is important in tumorigenesis of PTC and that it may serve to be an important target for identification and treatment of aggressive tumors. (Cancer Sci 2012; 103: 464–471)