Siu Kwan Ng

The Chinese University of Hong Kong, Hong Kong, Hong Kong

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Publications (8)72.72 Total impact

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    ABSTRACT: Foxp3+ regulatory T cells (Tregs) in lymphocytes facilitate the thyroid tumor growth and invasion. Very limited information is available on Foxp3 expression in thyroid cancer cells and its function is totally unknown. This study demonstrated that Foxp3 expression was increased in thyroid cancer cells. Inhibition of Foxp3 decreased cell proliferation and migration, but increased apoptosis, suggesting a positive role of Foxp3 in cancer growth. Interestingly, Foxp3 inhibition enhanced PPARγ expression and activity. In addition, Foxp3 inhibition downregulated NF-κB subunit p65 and cyclin D1 but upregulated caspase-3 levels. These molecular changes are in line with Foxp3 shRNA-mediated alteration of cell functions. Collectively, our study demonstrates that thyroid cancer cells express a high level of functional Foxp3 and that the inhibition of the Foxp3 suppresses the proliferation and migration but promotes apoptosis, suggesting that targeting Foxp3 in thyroid cancer cells may offer a novel therapeutic option for thyroid cancer.
    Molecular and Cellular Endocrinology 10/2014; · 4.04 Impact Factor
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    ABSTRACT: Estrogen receptor (ER) and peroxisome proliferator-activated receptor gamma (PPARγ) are associated with thyroid tumorigenesis and treatment. However, the interaction between them has not been studied. The impact of ER over-expression or down-expression by DNA/small interfering RNA (siRNA) transfection, ERα agonists, and the ERβ agonist diarylpropiolnitrile (DPN) on PPARγ expression/activity was examined in papillary thyroid carcinoma (PTC) and anaplastic thyroid carcinoma (ATC) cells. The effects of PPARγ modulation by rosiglitazone (RTZ), a PPARγ ligand, and of PPARγ siRNA on ER expression were determined. Cellular functions reflected by cell proliferation and migration were assayed. Apoptosis was analyzed by terminal deoxynucleotidyl transferase dUTP nick-end labeling, and apoptotic-related proteins were evaluated by Western blot analysis. PPARγ protein and activity were reduced by the over-expression of either ERα or ERβ, whereas repression of ERα or ERβ increased PPARγ expression. The administration of RTZ counteracted the effects of ER and also reduced their expression, particularly in PTC cells. Moreover, knockdown of PPARγ increased ER expression and activity. Functionally, ERα activation offset the inhibitory effect of PPARγ on cellular functions, but ERβ activation aggregated it and induced apoptosis, particularly in PTC cells. Finally, the interaction between ERβ and PPARγ enhanced the expression of proapoptotic molecules, such as caspase-3 and apoptosis-inducing factor. This study provides evidence supporting a cross-talk between ER and PPARγ. The reciprocal interaction between PPARγ and ERβ significantly inhibits the proliferation and migration of thyroid cancer cells, providing a new therapeutic strategy against thyroid cancer. Cancer 2013. © 2013 American Cancer Society.
    Cancer 10/2013; · 5.20 Impact Factor
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    ABSTRACT: To evaluate the feasibility of a one-stop assessment of patients complaining of globus sensation with transnasal esophagoscopy (TNE) and functional endoscopic evaluation of swallowing (FEES). Prospective, nonrandomized, experimental investigation. Tertiary referral centre. Sixty-three consecutive patients complaining of a lump in the throat were evaluated by this combined approach. The safety and feasibility of performing a one-stop TNE plus FEES were explored by subjective measurement of the patients' tolerance and satisfaction and comments from surgeons. The possible therapeutic effects were also assessed 2 months after the procedure. All 63 patients completed the TNE and FEES without any complications. The average duration of the examination was 6.27 ± 2.52 (95% CI 5.63-6.91) minutes. The findings included arytenoid cyst, epiglottic cyst, vocal cord nodules, vocal cord palsy, esophageal reflux, and foveolar gland hyperplasia. Two patients (3.2%) demonstrated some degree of fluid penetration or aspiration. Nine specialists all scored highly on a visual analogue scale on the manipulation, visualization, and satisfaction of the TNE procedure (median  =  8 of 10). Patients also rated a low pain score (median  =  1 of 10) and a high satisfaction score (median  =  9 of 10). The combined technique of TNE and FEES can be used safely as a one-stop examination tool for patients with globus pharyngeus symptoms.
    Journal of otolaryngology - head & neck surgery = Le Journal d'oto-rhino-laryngologie et de chirurgie cervico-faciale 02/2012; 41(1):46-50. · 0.71 Impact Factor
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    ABSTRACT: Transcutaneous vocal cord injection is a popular treatment choice for patients suffering from unilateral vocal cord paralysis. Transcutaneous transcartilaginous (through the thyroid cartilage) approach abolishes any anatomical constraint to reach the vocal cord. However it is a largely blind procedure as the needle should stay submucosal. Herein we report our experience in employing ultrasound guidance to circumvent this problem. Retrospective review of a series of 8 patients who underwent combined ultrasound/endoscopy-assisted vocal cord injection for unilateral vocal cord paralysis. Vocal cord injections were successfully completed in all but one patient. There were no associate complications. The use of ultrasound in aiding transcutaneous transcartilaginous vocal cord injection is safe and feasible. • Vocal cord injection is effective in treating unilateral vocal cord paralysis • A number of transcutaneous approaches with the patient awake have been described • Transcutaneous transcartilaginous approach theoretically has minimal anatomical restraint to reach the vocal cord • Disadvantage of that approach is the difficulty to accurately position the needle • Our experience of using ultrasound to circumvent this problem is positive.
    European Radiology 12/2011; 22(5):1110-3. · 4.34 Impact Factor
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    ABSTRACT: To determine the reproducibility of the Brodsky grading scale and the modified 3-grade and 5-grade scales in reporting the size of the tonsils. Retrospective review of 60 video recordings of tonsil examination by 12 independent observers with different clinical backgrounds and various levels of training. The sizes of the tonsils were graded using different grading scales. Tertiary care university hospital. The video recordings were chosen from an ongoing epidemiologic study of sleep-related breathing disorder in children in Hong Kong. Main Outcomes Measures The intraobserver and interobserver reproducibility of each grading scale was determined using intraclass correlation. An intraclass correlation coefficient (ICC) exceeding 0.75 was set a priori to indicate an acceptable level of reliability. The mean intraobserver ICCs for the Brodsky grading scale and the modified 3-grade and 5-grade scales were 0.858, 0.830, and 0.865, respectively. The mean interobserver ICCs for the Brodsky grading scale and the modified 3-grade and 5-grade scales were 0.763, 0.739, and 0.783, respectively. The Brodsky grading scale and the modified 5-grade scale achieved acceptable intraobserver and interobserver reproducibility.
    Archives of otolaryngology--head & neck surgery 02/2010; 136(2):159-62. · 1.92 Impact Factor
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    ABSTRACT: Aim: To establish a transoral robotic surgery (TORS) programme for the surgical management of head and neck pathology including oropharyngeal lesions, and to carry out a TORS tonsillectomy.Methods: Training for otolaryngologists was planned and undertaken. Off-site robotic training of otolaryngologists was conducted by a robotic company trainer. Visits to established international TORS programmes were made. A suitable patient was identified with the intention of undergoing a TORS tonsillectomy and evaluating the outcome.Results: A patient successfully underwent a transoral robotic surgery tonsillectomy using a surgical robot system without intraoperative or postoperative complications or sequelae.Conclusions: A transoral robotic surgery programme, including training for otorhinolaryngologists, has been established. A tonsillectomy, a feasible procedure easily carried out, was done using a surgical robot system without complications.
    Surgical Practice 01/2009; 13(1):17 - 19. · 0.11 Impact Factor
  • New England Journal of Medicine 09/2005; 353(6):e5. · 54.42 Impact Factor
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    ABSTRACT: To investigate whether autologous ossicles can be safely used in ossicular reconstruction in cholesteatoma surgery after attempting cholesteatoma removal under the operating microscope. A prospective fine-section histological study of formalin-stored ossicles, harvested from cholesteatomatous ears, to evaluate for existence of residual cholesteatoma after surface disease clearance under the operating microscope. One hundred four ossicles were harvested from 76 patients with cholesteatoma for the study. These malleus heads and includes were categorized into three groups: group 1, ossicles with retained shape and useful bulk, treated by microscopic stripping alone; group 2, ossicles with retained shape and useful bulk, treated by microscopic stripping and drilling; and group 3, badly eroded ossicles, treated by microscopic stripping alone. These treated ossicles were then subjected to 4 microm histopathological study. Residual disease was identified in 6 of the 104 ossicles. Residual disease was found only in badly eroded ossicles that are not suitable for reconstruction. All the usable ossicles were free of disease. Autologous ossicles that have retained body and bulk are safe to use for reconstruction after surface stripping under the operating microscope. Additional burring probably adds a further margin of safety.
    The Laryngoscope 06/2003; 113(5):843-7. · 1.98 Impact Factor