C A van Hasselt

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

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Publications (267)428.55 Total impact

  • [Show abstract] [Hide abstract]
    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
  • Willis S Tsang, John K Woo, C Andrew van Hasselt
    Ear, nose, & throat journal 10/2014; 93(10-11):452. · 1.03 Impact Factor
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    ABSTRACT: The present study validates and evaluates the sensitivity and specificity of four internationally popular questionnaires, translated into Chinese, for assessing suspected obstructive sleep apnea (OSA) patients, namely, the Berlin questionnaire, the ASA checklist, the STOP questionnaire and the STOP-BANG questionnaire. Their predictive values in OSA risks in patients presenting with OSA symptoms are examined. Questionnaires may be helpful in prioritizing polysomnography (PSG) and in treatment for the more severe cases.
    09/2014;
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    ABSTRACT: This study aimed at investigating (1) tone perception development among typically-developing Cantonese speakers and (2) the hierarchy of tone perception difficulty among the 15 tone contrasts. Two-hundred typically-developing children aged 3-10 and a group of 25 normal hearing adults were recruited. They were tested on a pool of 75-item calibrated recorded speech signals. Participants responded to each stimulus by pointing at the corresponding picture displayed on a computer screen from a choice of four. There was a gradual increase in tone perception accuracy from children aged 3-6. After age 6, tone perception accuracy was similar to adults with an average error rate of 3-8%. The two tone contrasts that listeners consistently found difficult to distinguish were T2T5 (high-rising vs low-rising) and T3T6 (mid-level vs low-level). In addition, all children groups also showed difficulty in T4T6 identification (low-falling vs low-level). Tone perception is not error-free even among native Cantonese-speaking adults. Overall tone identification performance improved steadily from age 3 to age 6. Based on the participants' performance, a three-tier set of tone groups, with an increasing level of difficulty for identification, is proposed for rehabilitation purposes. These tone groups are (1) Easy: T1T2, T1T3, T1T4, T1T5, T1T6, and T2T3, (2) Medium: T2T4, T2T6, T3T4, and T4T5, and (3) Hard: T2T5, T3T5, T3T6, T4T6, and T5T6.
    International Journal of Speech-Language Pathology 04/2014; · 1.18 Impact Factor
  • Alexander C Vlantis, Eddy W Y Wong, C Andrew van Hasselt
    Otolaryngology Head and Neck Surgery 11/2013; · 1.73 Impact Factor
  • Willis S Tsang, Michael C Tong, C Andrew van Hasselt
    Ear, nose, & throat journal 02/2013; 92(2):E27. · 1.03 Impact Factor
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    ABSTRACT: Objective This study examines subjects' level of consciousness with bispectral analysis in sedation endoscopy of the upper airway.Study DesignA prospective study.SettingUniversity hospital.Subjects and Methods Bispectral analysis levels recorded in natural sleep of 43 patients with obstructive sleep apnea during an overnight polysomnographic sleep study were directly compared with the levels recorded during midazolam sedation sleep endoscopy in the same subjects. The possible muscle relaxation effect of midazolam was examined via surface chin electrodes. Supine Müller maneuver findings in 50 patients with obstructive sleep apnea were also compared with soft tissue dynamics during midazolam sedation sleep endoscopy.ResultsIn our study of the 43 patients with bispectral analysis during natural sleep and midazolam sedation sleep endoscopy, a predominance of bispectral analysis values indicating N1 and N2 sleep was observed during the sedation study. Midazolam failed to achieve deeper levels of sleep with minimal N3 and no convincing rapid eye movement. As N1 and N2 are the stages during which maximal dynamic activities occur, and they make up an average of 70.5% of total sleep time, from 210 sleep studies at our laboratory, the present technique would be ideal as a surgical assessment tool. No muscle relaxation effect could be detected at our protocol dose of midazolam. The supine Müller maneuver findings were significantly different from those observed during sedation sleep.Conclusion These findings support the value of sleep endoscopy as an efficient and informative technique for the examination of upper airway dynamics relevant to focused surgical planning.
    Otolaryngology Head and Neck Surgery 10/2012; · 1.73 Impact Factor
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    ABSTRACT: The substantial T lymphocyte infiltrate found in cases of nasopharyngeal carcinoma (NPC) has been implicated in the promotion of both tumor growth and immune escape. Conversely, because malignant NPC cells harbor the Epstein-Barr virus, this tumor is a candidate for virus-specific T cell-based therapies. Preventing the accumulation of tumor-promoting T cells or enhancing the recruitment of tumor-specific cytotoxic T cells offers therapeutic potential. However, the mechanisms involved in T cell recruitment to this tumor are poorly understood. Comparing memory T cell subsets that have naturally infiltrated NPC tissue with their counterparts from matched blood revealed enrichment of CD8(+), CD4(+), and regulatory T cells expressing the chemokine receptor CXCR6 in tumor tissue. CD8(+) and (nonregulatory) CD4(+) T cells also were more frequently CCR5(+) in tumor than in blood. Ex vivo studies demonstrated that both receptors were functional. CXCL16 and CCL4, unique chemokine ligands for CXCR6 and CCR5, respectively, were expressed by the malignant cells in tumor tissue from the majority of NPC cases, as was another CCR5 ligand, CCL5. The strongest expression of CXCL16 was found on tumor-infiltrating cells. CCL4 was detected on the tumor vasculature in a majority of cases. These findings suggest that CXCR6 and CCR5 play important roles in T cell recruitment and/or retention in NPC and have implications for the pathogenesis and treatment of this tumor.
    American Journal Of Pathology 03/2012; 180(3):1215-22. · 4.60 Impact Factor
  • Siu Kwan Ng, Hok Yuen Yuen, Charles A van Hasselt, Anil Ahuja
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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: BACKGROUND: Sinus histiocytosis with massive lymphadenopathy or Rosai-Dorfman disease (RDD) is a rare benign disease with nodal and extranodal involvement. METHODS AND RESULTS: Herein, we report 3 cases in which the patients presented with nasal masses. In addition, 2 of the 3 patients had subglottic lesions. Only 2 of the 3 patients had cervical lymphadenopathy, which is the commonest presentation of RDD. Histopathology via fine-needle aspiration cytology (FNAC) or open biopsy is required for diagnosis. Emperipolesis with S-100 immunohistochemical staining is characteristic. The disease runs a benign course and the literature reports that treatment can vary from steroids, to cytotoxic chemotherapy to radiotherapy with variable outcomes. Surgical intervention may be necessary for airway protection. CONCLUSION: RDD is self-limiting, but can sometimes be a life-threatening condition. Treatment should be tailored to the individual patient. © 2011 Wiley Periodicals, Inc. Head Neck, 2011.
    Head & Neck 11/2011; · 2.83 Impact Factor
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    ABSTRACT: There is a paucity of knowledge on dysphagia in patients with nasopharyngeal carcinoma postradiotherapy (NPC post-RT). The purpose of this study was to establish silent aspiration occurrence, safe bolus consistency, and their relationship with swallowing physiology in patients with dysphagic NPC post-RT. Eighty-five patients with dysphagic NPC post-RT were assessed across 4 bolus consistencies. We compared penetration-aspiration scores against 4 swallowing physiology impairments. Silent aspiration occurred in 65.9% of patients with dysphagia, with 64.7% on thin fluids, 35.3% on thick fluids, 11.8% on pureed diet, and 5.9% on soft diet. Multivariate analysis of variance (MANOVA) indicated pharyngeal contraction and swallowing response had significant effect on thick fluids (p = .002), thin fluids (p = .017), and soft diet (p = .031). Silent aspiration of thin fluids is a common occurrence in dysphagic NPC post-RT, with least aspiration noted on soft diet. Considering the high incidence of silent aspiration, instrumental assessment in this cohort is crucial.
    Head & Neck 09/2011; 33(9):1335-9. · 2.83 Impact Factor
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    ABSTRACT: Background The purpose of this study was to identify independent prognostic factors that influenced local relapse-free survival (LRFS) and overall survival (OS) of patients who underwent salvage surgery for residual or recurrent nasopharyngeal carcinoma (NPC).Methods Ninety-seven patients who had been treated with radiotherapy or chemoradiotherapy for NPC underwent a nasopharyngectomy for a residual or recurrent local tumor between November 1987 and June 2007. The subsequent minimum follow-up was 2 years. Univariate and multivariate analyses were performed to identify prognostic factors for LRFS and OS.ResultsThe 5-year LRFS and OS was 46.7% and 51.9%, respectively. On multivariate analysis for LRFS and OS, respectively, recurrent regional disease (hazard ratio [HR], 3.245; p = .008) and (HR, 4.990; p = .001), and positive surgical margins (HR, 5.963; p = .000), and (HR, 4.912; p = .000) were independent prognostic factors.Conclusion In patients undergoing surgical salvage nasopharyngectomy for residual or recurrent NPC, positive surgical margins have an independent negative influence on LRFS and OS. © 2010 Wiley Periodicals, Inc. Head Neck, 2011
    Head & Neck 07/2011; 33(8):1126 - 1131. · 2.83 Impact Factor
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    ABSTRACT: The purpose of this study of human papillomavirus (HPV), Epstein-Barr virus (EBV), p21, and p53 in sinonasal inverted papilloma (IP) was to help elucidate its pathogenesis. Seventy-three IPs, 48 nasal polyps, and 85 hypertrophied turbinates were subjected to HPV polymerase chain reaction (PCR) study. Seventy-three IPs, 30 nasal polyps, and 32 hypertrophied turbinates were subjected to EBV in situ hybridization (ISH), p21, and p53 immunohistochemical (IHC) studies. HPV was positive in 3 of 73 IPs (4.1%). All specimens were EBV negative. In all, 99% of IPs showed strong and diffuse p21 nuclear reactivity. Most nasal polyps and hypertrophied turbinates showed weak to moderate immunoreactivity of the basal and parabasal cells. Only focal p53 immunoreactivity of the basal and parabasal cells was found in 19% of IPs and 40% of nasal polyps. HPV prevalence of our IP is low. EBV is not present in IP. High p21 and low p53 expression in IP suggests a non-p53-dependent regulation pathway.
    Head & Neck 05/2011; 34(4):520-33. · 2.83 Impact Factor
  • Willis S S Tsang, Michael C F Tong, C Andrew van Hasselt
    Ear, nose, & throat journal 02/2011; 90(2):E29. · 1.03 Impact Factor
  • A.-C. Vlantis, H. Gao, E. Wong, E. Ng, P. Chiu, C.-A. van Hasselt
    Oral Oncology - ORAL ONCOL. 01/2011; 47.
  • A.-C. Vlantisp, W.-F. Bower, T. Chung, C.-A. van Hasselt
    Oral Oncology - ORAL ONCOL. 01/2011; 47.
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    ABSTRACT: Objective : To determine the incidence of otitis media with effusion and the associated hearing loss, the rate of ventilation tube insertion, and complications of ventilation tube insertion in Chinese cleft palate patients. Design : Retrospective review in a tertiary care hospital in Hong Kong. Patients : A total of 104 consecutive patients with cleft lip and/or cleft palate who were born between January 1996 and January 2006. Results : The incidence of otitis media with effusion in Chinese cleft palate patients for the first 2 years after birth was 76.1%. Of these patients, 16.9% had otitis media with effusion associated with a moderate hearing loss (>40 decibels hearing level [dBHL]). Approximately half (53.2%) of our patients had ventilation tube insertion. Complications including retraction, tympanosclerosis, and perforation of the tympanic membrane were found in 15.7% of all ears with otitis media with effusion and ventilation tube insertion. Conclusions : The high incidence of otitis media with effusion in cleft palate infants found in this study is consistent with that reported in the Western literature. A small but significant proportion of otitis media with effusion was associated with moderate hearing loss that truly required surgical treatment. Cleft palate children are much more likely to develop otitis media with effusion than normal children, and they develop the condition at an earlier age. A protocol for the treatment of otitis media with effusion in cleft palate patients and further prospective studies are warranted.
    The Cleft Palate-Craniofacial Journal 01/2011; 48(6):684-9. · 1.24 Impact Factor
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    ABSTRACT: We report a case of otogenic fungal pachymeningitis in a diabetic patient who presented with multiple cranial nerve palsies and nasopharyngeal swelling. We present a case report, we describe the investigations, management and clinical course of fungal pachymeningitis, and we present a review of the world literature on fungal and non-fungal pachymeningitis. To our knowledge, this is the first report of fungal pachymeningitis with magnetic resonance imaging features suggestive of nasopharyngeal carcinoma. It is also the first reported case with aspergillus cultured from both a dural biopsy and the ear canal. Fungal pachymeningitis is a rare condition which may present to otorhinolaryngologists. Its clinical and radiological findings can be confused with those of nasopharyngeal carcinoma; fungal pachymeningitis should thus be included in the differential diagnosis of nasopharyngeal carcinoma.
    The Journal of Laryngology & Otology 01/2011; 125(1):103-7. · 0.68 Impact Factor
  • Kathy Y S Lee, Charles Andrew van Hasselt, Michael C F Tong
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    ABSTRACT: In tone languages such as Cantonese, a change in tone denotes a change in lexical meaning. The present study investigates the functional benefit of hearing devices in assisting tone perception among children with profound hearing impairment. Fifty-two children with profound hearing loss were categorized into two groups based on their primary type of hearing device - a hearing aid group and cochlear implant group. A 75-item tone identification test covering all 15 Cantonese tone contrast pairs was administered to each subject under two conditions - unaided (hearing devices turned off) and aided (devices turned on). The proportion of correct responses was computed as the total score for all items and subtotal contrast scores for each of the 15 tone contrasts. The results indicated no significant differences between the children wearing hearing aids and those with cochlear implants under the unaided or the aided condition (z = -0.91, p = 0.36; z = -0.40, p = 0.69, respectively). Regardless of the type of device used, the total scores under the aided condition were higher than those under the unaided condition (z = -3.55 for the hearing aid group; z = -4.87 for the cochlear implant group, both ps < 0.01). Children wearing hearing devices generally have a satisfactory functional gain in tone perception. No major observable difference was noted between children using cochlear implants and those using hearing aids. Tone contrast pairs with dissimilar fundamental frequency at onset and dissimilar tone contour patterns were more easily identified.
    Otology & neurotology: official publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology 09/2010; 31(7):1079-87. · 1.44 Impact Factor
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    ABSTRACT: Normal nasopharyngeal mucosa contains varying amounts of lymphoid tissue, which in adults may be minimal or absent. Nasopharyngeal mucosa with minimal lymphoid tissue has a regular follicular pattern on narrow-band imaging; pale follicles have thin, dark borders and the ratio of the pale follicle to the dark border (pale-to-dark ratio) is roughly 90%. In some patients undergoing routine nasopharyngeal endoscopy, the pale-to-dark ratio is reversed on narrow-band imaging, with dark centres surrounded by pale borders and a pale-to-dark ratio of roughly 50%. These dark follicles may represent abnormal capillary loops, as they have the same appearance as microvascular changes seen on narrow-band imaging of the oesophageal mucosa which indicate dysplasia or malignancy. While this observed change in the follicular pattern may be an early event in the evolution of nasopharyngeal carcinoma, the significance of this finding remains to be confirmed by a larger-scale study.
    Hong Kong medical journal = Xianggang yi xue za zhi / Hong Kong Academy of Medicine 08/2010; 16(4):307-9.

Publication Stats

2k Citations
428.55 Total Impact Points

Institutions

  • 1990–2013
    • The Chinese University of Hong Kong
      • • Department of Otorhinolaryngology, Head & Neck Surgery
      • • Department of Surgery
      • • Prince of Wales Hospital
      Hong Kong, Hong Kong
  • 2012
    • Christian Hospital
      Saint Louis, Michigan, United States
  • 2011
    • Lands Department of The Government of the Hong Kong Special Administrative Region
      Hong Kong, Hong Kong
  • 2010
    • Chongqing Medical University
      Ch’ung-ch’ing-shih, Chongqing Shi, China
  • 1991–2008
    • Prince of Wales Hospital, Hong Kong
      Chiu-lung, Kowloon City, Hong Kong
  • 2002
    • University of Melbourne
      Melbourne, Victoria, Australia
  • 2001–2002
    • Alice Ho Miu Ling Nethersole Hospital
      Ch’üan-wan, Tsuen Wan, Hong Kong
  • 1999–2000
    • University of Adelaide
      • Discipline of Otolaryngology, Head and Neck Surgery
      Adelaide, South Australia, Australia
  • 1994
    • University of Queensland
      Brisbane, Queensland, Australia
  • 1992–1993
    • Caritas Hong Kong
      Chiu-lung, Kowloon City, Hong Kong