Youngho Jung

Clinical Manifestations of Recurrent Parotid Pleomorphic Adenoma

Objectives This study was undertaken to confirm the clinical characteristics of recurrent pleomorphic adenoma (RPA), and to identify those factors that affect the development of malignant transformation (MT) from RPA. Methods The medical records of 270 patients, who were operated upon for parotid PA, were retrospectively reviewed. The pathologic specimens of a selected series of 23 patients were reviewed for histologic subtype and microscopic multi-nodularity. Results Mean age of initial operation in RPA without MT (RPA-MT) group was significantly lower than that of primary PA group. Mean age of the revision operation in RPA with MT (RPA+MT) group was significantly greater than that of RPA-MT group. Mean interval from operation to recurrence shortened after each revision operation. The risk of MT and additional recurrence increased significantly with recurrence. In RPA-MT group tumor recurrence occurred in 21.4% of patients despite a clear resection margin. Conclusion The risk factors for MT may be an age of over 45 yr and multiple recurrences. However, younger patients are more at risk of recurrence. A clear resection margin cannot guarantee a cure in RPA, and it seems that parotid pleomorphic adenomas slowly gain malignant characteristics after repeated recurrences.

Expression of cancer stem cell markers is more frequent in anaplastic thyroid carcinoma compared to papillary thyroid carcinoma and is related to adverse clinical outcome

Background Thyroid cancer is one of the most commonly detected cancers worldwide, and papillary thyroidal carcinoma (PTC) accounts for the majority of thyroid cancers. In contrast to the indolent nature of PTC, anaplastic thyroid carcinoma (ATC) shows an extremely poor prognosis and has not responded to any therapeutic modalities. Many researchers postulate that the dedifferentiation of thyroid follicular cells into primitive cells might be related to the pathogenesis of ATC because several cases of ATC have revealed pre-existing PTC lesions. Additionally, the cancer stem cell (CSC) theory has been widely accepted in the pathogenesis of ATC. Objective To explore the expression of various CSC markers in thyroid carcinoma tissues and analyse their clinical significance. Methods 133 patients with PTC and 25 patients with ATC were enrolled. Immunohistochemistry for aldehyde dehydrogenase 1 (ALDH1), CD133, CXCR4, ATP-binding cassette (ABC)G2, multidrug resistance associated protein-1 (MRP1), lung resistance protein-1 (LRP), P-glycoprotein 1 (P-Gp1), SOX2, SOX9 and Oct4 was performed using tissue microarray. Results CSC marker expression was significantly high in ATC, particularly chemoresistance markers such as ABCG2, MRP1, LRP and CXCR4. In PTC, ABCG2 was highly positive in more advanced pathological stages and was associated with lymph node involvement, with borderline significance. In ATC, high expression of CXCR4 correlated with distant metastasis, and LRP showed a tendency to correlate with lymph node metastasis. High expression of CSC markers was related to shorter overall survival in patients with ATC. Conclusions These results provide strong evidence that CSCs are related to the pathogenesis of ATC and can explain the frequent treatment failure and aggressiveness of ATC.

Prevalence of ocular symptoms in patients with allergic rhinitis: Korean multicenter study.

Background Allergic rhinitis (AR) is often accompanied by multiple ocular symptoms. This study aimed to evaluate the prevalence of ocular symptoms and the impact of ocular symptoms on the quality of life in patients with AR. Methods One thousand one hundred seventy-four patients with AR were enrolled from 24 centers in Korea. They were classified into four groups according to the Allergic Rhinitis and Its Impact on Asthma (ARIA) guideline and also classified into perennial AR (PAR) and seasonal AR groups. All patients were asked to complete the questionnaire regarding the presence of ocular symptoms, such as eye itching, watery eyes, and red eyes. The correlation between ocular symptoms and the rest of the quality-of-life areas in the Mini-Rhinoconjunctivitis Quality of Life Questionnaire (Mini-RQLQ) was also asked. Results Seven hundred nineteen (61.2%) of 1174 patients had ocular symptoms. In detail, the numbers of patients with eye itching, watery eyes, red eyes, and other ocular symptoms were 605 (51.5%), 313 (26.7%), 207 (17.6%), and 66 (5.6%), respectively. Female patients (72.5%) complained of ocular symptoms more commonly than male patients (55.1%). The patients with moderate–severe persistent AR showed the highest prevalence of ocular symptoms. The correlation coefficients between ocular symptoms and the rest of the quality-of-life areas in the Mini-RQLQ were statistically significant (p < 0.05). Conclusion Sixty-one percent of Korean AR patients experienced ocular symptoms. The patients who were women and had PAR and more severe AR showed higher prevalence of ocular symptoms. The ocular symptoms might have a significant impact on the quality of life in patients with AR.

MOS varactor modeling for mm-Wave applications

A RF MOS varactor model has been verified in mm-wave range in this paper. Since this non linear model consisted of the SPICE compatible lumped elements with physical meanings has a single topology and simple equations, it can be easily implemented in commercial circuit simulators. Based on the S-parameter measurement, the efficient and accurate parameter extraction methodology from analysis for Z-parameters on this equivalent circuit was developed and successfully validated up to 110 GHz.

P24.08: Prenatal sonographic diagnosis of congenital arachnoid cyst: clinical outcomes in a tertiary care centre

Objectives: To investigate the prenatal ultrasonographic(US) findings which are associated to abnormality and neonatal outcome of 21 fetuses with congenital arachnoid cysts(CAC) diagnosed antenatally. Methods: A retrospective study of all cases which were prenatally and postnatally diagnosed as CACs was performed in patients referred to the Severance Hospital from November 2005 to December 2016. Results: 17 CAC fetuses were identified by US at the median gestational age of 30 weeks (range 24-38). Of the 17 probable CAC, 11 (64.7%) cases were diagnosed with CAC and 6 cases were confirmed with other diagnosis based on MRI finding. 4 cases were misdiagnosed as other different disease based on prenatal US. 3 (75%) of the 4 misdiagnosed cases were confirmed postnatally as posterior fossa CAC and 1 case was confirmed as intraventricular arachnoid cyst. In terms of location, 7 (46.7%) had CAC in posterior fossa. Of the 15 confirmed CAC, only one case presented agenesis of the corpus callosum and two cases presented secundum atrial septal defect and ventricular septal defect. None of the 15 cases was confirmed as chromosomal abnormality. For 6 cases, conservative management was done, while other 9 babies, fenestration of CAC was performed. In 4 of the 9 cases, surgery was performed in the second week of life (day 6 to 12). Because of enlarged CAC with aggravated symptoms, 4 needed subsequent cystoperitoneal shunt. Conclusions: Depending on the location of CAC, it can be diagnosed incorrectly as other disease with similar US finding. According to our study and previous literature, the prognosis of CAC depends on the presence of the corpus callosum or other congenital malformations, and the progression of ventriculomegaly. Therefore, if CAC is suspected, it is necessary to conduct the detailed US screening for congenital malformation. Also, there is a need for proper consultation for parents with regard to the possibility of surgery after delivery.

Integrated LC VCO Compatible with Memory Process for Gigahertz Clock Generation

This work presents the design and fabrication of the LC voltage-controlled oscillator (VCO) using 1-poly 3-metal CMOS process aimed for use in current memory manufacturing process. Poor characteristics of highly-resistive and immune to substrate-coupling metal-3 inductor in LC resonator were overcome by dual metal structure and patterned-ground shield (PGS) strategy. Fabricated VCO operated from 2.48 GHz to 2.73 GHz tuned by accumulation-mode MOS varactor. The corresponding tuning range was 250 MHz. The measured phase noise was - 113.5 dBc/Hz at 1 MHz offset at 2.48 GHz carrier frequency. The current consumption and corresponding power consumption were about 1.04 mA and 1.87 mW respectively.